A pulley in the form of a uniform disk)
with mass 63 kg and a radius 20 cm is at-
tached to the ceiling in a uniform gravita-
tional field and rotates with no friction about
its pivot. The masses are connected by a
massless inextensible cord and T1, T2, and T3
are magnitudes of the tensions.
T3
20 cm
T2
63 kg
1
39 kg
T1
3.8 m
15 kg
2
What is the magnitude of the tension T?
The acceleration due to gravity is 9.8 m/s?.
Assume up is positive.
Answer in units of N.

Answers

Answer 1

For a  pulley in the form of a uniform disk with a mass of 63 kg and a radius of 20 cm, the magnitude of the tension T is mathematically given as

T1=292.4N

What is the magnitude of the tension T?

For 20kg

T1=196+20a

For

33kg

T2=323.4-33a

Generally, the simultaneous equation is mathematically given as

T2-T1=(323.4-33a)-(196+20a)

Hence

127.4-53.a

a=1.67m/s^2

T1=196+20(1.67)

T1=292.4N

In conclusion, the magnitude of the tension T

T1=292.4N

Read more about Tension

https://brainly.com/question/9410676


Related Questions

A 400 N student climbs up a 3.0 m ladder in 4.0s.

a)How much work does the student do?

b)What is the student’s power output?

Answers

Answer:

We are given that the student has a weight of 400N

So, the force applied by the boy has to be added to 400 since he has to apply force to keep his body on the stairs

We are given:

u = 0 m/s

v = v m/s

t = 4 s

a = a m/s/s

s = 3 m

w = 400 N

Converting to Mass

w = m * g    (where m is the actual mass and g is the value of gravity)

letting g = 10m/s/s

400  = 10 * m

m = 40 kg

Finding Acceleration:

From the second equation of motion:

s = ut + (a*t*t) / 2

3 = (0)(4) + (a)(4)(4)/2

3 = 8a

a = 3/8 m/s/s

Force Applied by the Student:

Now that we have the acceleration, we can find the force applied by the student to go up the stairs

F = ma (Newton's second law of motion)

F = (40)(3/8)

F = 15 N

Hence, the student is applying 15N to climb up the stairs and another 400 N to support his mass

Total Force applied by the Student:

F(total) = F(climbing) + F(weight)

F(total) = 15 + 400

F(total) = 415 N

Work done by the Student:

Work done = F.S   (dot product of force applied and displacement)

Work done = (415)(3)

Work done = 1245 Joules

Power Output of the Student:

power output is the amount of work done per second

Power = Work Done / t

Power = 1245 / 4

Power = 311.25 Watt

**note that the this is just the power consumed by the student to climb the stairs**

During meiosis maternal and paternal chromosomes that occur in a gamete line up and exchange segments in a process called crossing over. Then they are randomly shuffled as the cell divides. This process results in

Answers

Explanation:

Crossing over is the swapping of genetic material that occurs in the germ line. During the formation of egg and sperm cells, also known as meiosis, paired chromosomes from each parent align so that similar DNA sequences from the paired chromosomes cross over one another.

Answer:

Explanation:

After cross-over, the chromosomes are randomly shuffled to the daughter cells as the cell divides. This process results in in gametes that with unique combinations of chromosomes and is called independent assortment.

What happens to pressure if temperature increases?

Answers

When the temperature increases the pressure must also increase.

The projectile motion of an object can
be described by two independent
vector components that are
______

Answers

Answer:

perpendicular

Explanation:

The projectile motion of an object can be described by two independent vector components that are horizontal and vertical motion.

What is projectile motion?

The motion of an item hurled or projected into the air, subject only to gravity's acceleration, is known as projectile motion.

The item is known as a projectile, and the course it takes is known as a trajectory. Falling object motion is a simple one-dimensional kind of projectile motion with no horizontal movement.

The projectile's motion is divided into two parts: horizontal and vertical motion.

Because perpendicular motion components are independent of one another, these two motion components may be treated individually.

Hence two independent vector components are horizontal and vertical motion.

To learn more about the projectile motion refer to the link;

https://brainly.com/question/11049671

If you double the size of the larger pad of a hydraulic system, how much less force do you need to apply to the smaller pad to achieve the same result?
A. 1/4 the force
B. 1/2 the force
C. 1/3 the force
D. The same amount of force

Answers

Answer:

A - ¼ of the force

Explanation:

According to Pascal’s principle, there's an equation that relates the force to area ratios in hydraulic systems, provided that the pistons will be at the same vertical height and that the friction in the given hydraulic system is negligible. This formula is;

F1/A1 = F2/A2

Thus;

F1/F2 = A1/A2

Where F is the applied force and A is area of pad.

Now, we are told that the size of the pad is doubled. Thus;

If the initial radius is r, then the new radius is 2r

Thus;

F1/F2 = (πr²)/(π(2r)²)

F1/F2 = r²/4r²

F1/F2 = ¼

F1 = ¼F2

Thus, the answer is ¼ of the force

A constant voltage of 11.00 V has been observed over a certain time interval across a 1.20 H inductor. The current through the inductor, measured as 1.00 A at the beginning of the time interval, was observed to increase at a constant rate to a value of 7.00 A at the end of the time interval. How long was this time interval

Answers

Answer:

0.65 sec

Explanation:

V = L*ΔI/Δt

so Δt = L*ΔI/V = 1.20 * (7.00 - 1.00)/11.00 = 0.65 sec

If Benjamin skated 80 kilometers at 10 kilometers per hour, how long was Benjamin skating? Express your answer in minutes

A: 240 minute

B: 480 minutes

C: 180 minute

Answers

Answer:

480

Explanation:

first simplefie 80 ÷10

now

8x 60

480

What kind of nutrient comes from water and air?
mineral nutrients
non-mineral nutrients

Answers

Answer:

The answer is non-mineral nutrients.

Answer:

non-mineral nutrients.

Explanation:

A balloon with a negative charge of -2.0×10-8 C is held 2 cm (0.02 m) below a rod with a positive charge of 2.0×10-8 C. What is the force between the balloon and the rod?

Answers

The force of attraction between the balloon and the rod is 9 x 10⁻³ N.

Force of attraction between the balloon and the rod

The force of attraction between the balloon and the rod is calculated by applying Coulomb's law as shown below;

[tex]F = \frac{kq_1 q_2}{r^2}[/tex]

where;

r is the distance between the chargesk is Coulomb's constant = 9 x 10⁹ Nm²/C²

F = (9 x 10⁹) x (2.0 x 10⁻⁸)²/(0.02)²

F = 9 x 10⁻³ N

Thus, the force of attraction between the balloon and the rod is 9 x 10⁻³ N.

Learn more about Coulomb's force here: https://brainly.com/question/24743340

[tex]\:\:\:\:\:\:\:\:\:\:\star [/tex]We can calculate the force between the balloon and the rod applying "Coulomb's Law". Which states-

[tex]\:\:\:\:\:\:\:\:\:\:\star\:\sf \underline{F_{(air)} = K\times \dfrac{ q_1 q_2}{r^2}} \\ [/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\star\:\sf\underline{F_{(air)} = \dfrac{1}{4\pi \epsilon_{0} } \dfrac{q_1q_2}{r^2} }\\ [/tex]

Where-

q₁ and q₂ are the two cahrges.r is the distance between the charges.[tex]\sf \epsilon_{0} [/tex] is the permittivity of free space.K is the Coulomb's Constant.k = 9×10⁹ Nm²/C²

As per question, we are given that -

q₁= 2.0 x 10⁻⁸Cq₂= -2.0 x 10⁻⁸CDistance,r = 0.02 m

Now that required values are given, so we can substitute the values into the formula and solve for Force -

[tex] \:\:\:\:\:\:\:\:\:\:\star\:\sf\underline{F_{(air)} = \dfrac{1}{4\pi \epsilon_{0} } \dfrac{q_1q_2}{r^2} }\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)}= 9\times 10^9 \times \dfrac{-2\times 10^{-8}\times 2\times 10^{-8} }{(0.02)^2}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)}= -9\times 10^9 \times\dfrac{4\times10^{-16}}{4\times 10^{-4}}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)}= -9\times 10^9 \times\dfrac{\cancel{4}\times10^{-16}}{\cancel{4}\times 10^{-4}}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)} = -9\times 10^9 \times 10^{-16} \times 10^{4}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)} = -9\times 10^9 \times 10^{-16+4} \\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)} = -9\times 10^9 \times 10^{-12} \\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)} = -9\times 10^{9-12}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf Force_{(air)} = -9\times 10^{-3}\\ [/tex]

[tex] \:\:\:\:\:\:\:\longrightarrow \sf \underline{Force_{(air)} = -9\times 10^{-3}\:N}\\ [/tex]

Therefore,the force between the balloon and the rod is -9 x 10⁻³ N.

A rock weighing 250N falls from a height of 16 m and falls towards the ground. Determine the momentum of the rock prior to striking the ground.

Answers

Answer: I'm not very good at all. I need help with determine the velocity of an object just before it hits the ground, given the object's mass and the distance it falls. For example, a .060 kg (or 60 g) ball falls from a 12 meter building. Also, assume it is free falling (no air resistance) and the average time it takes to hit the ground it 1.16 seconds.

Explanation:

Time management skills include
A. A personal mission statement, prioritizing, and deep breathing.
B. Setting objectives, knowing your limits, and reviewing.
C. Avoiding distractions, setting dreams, and budgeting time.
D. Budgeting time, avoiding stress, and prioritizing.

Answers

D. Budgeting time, avoiding stress, and prioritizing.

Answer:

D.

Explanation:

Budgeting time, avoiding stress, and prioritizing.

Can someone help me please :( ASAP. Also I’m sorry if it’s small

Answers

Answer:

Graph #2

Explanation:

Notice, on the position time graph, there is a constant rate of change. This means that there is a constant velocity, meaning it's a straight line. The line is decreasing so the velocity will be negative.

If a 50 N block experiences a force of kinetic friction of 11 N
from the surface of a table, then what is the coefficient of
kinetic friction () between the block and the table?

Answers

Answer:

F(friction) = μ M g         definition of frictional force

μ  = F / (M g) = 11 N / 50 N = .22

The co-efficient of kinetic friction between the block and the table is 0.22.

To find the co-efficient of friction, the given values are,

Friction force - 11 N

Normal force - 50 N

What is Friction force?The forces acting with the force of gravity, normal and the force of friction. Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.We know that the frictional force is the force that opposes the motion of an object.Frictional Force refers to the force generated by two surfaces that contact and slide against each other.F(friction) = μ M g F - frictional forceM g = N - Normal force ( M g - Mass and the acceleration due to gravity)μ - Coefficient of frictioncoefficient of kinetic friction = friction force / normal force

         μ = 11 N / 50 N

             = 0.22

Thus, the co-efficient of the kinetic friction is 0.22

Learn more about frictional force,

https://brainly.com/question/1714663

#SPJ2

The current is 0.720 A in a circuit in which a battery of emf 12.0 V is connected to a resistor of resistance 14.5 Ω. Find the potential difference across the terminals of the battery.

Answers

Answer:

explain the meaning of the term work done and give an example of where work is done

what were formed after the big bang theory?​

Answers

Answer:

neutrons protons electrons

Explanation:

after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.

The temperature of a cup of coffee varies according to Newton's Law of Cooling: dT dt equals negative k times the quantity T minus A, where T is the temperature of the coffee, A is the room temperature, and k is a positive constant. If the coffee cools from 100°C to 90°C in 1 minute at a room temperature of 25°C, find the temperature, to the nearest degree Celsius of the coffee after 4 minutes.

74
67
60
42

Answers

Answer:

Explanation:

Writing out the Newton's Law pf Cooling:

dT/dt = -k * (T - A),

where T is the temperature of the coffee, A is the room temperature, and k is a positive constant.

If the coffee cools from 100°C to 90°C in 1 minute at a room temperature of 25°C,

T = 100

A = 25

dT = 100 - 90 = 10

dt = 1

Putting the figures into the equation:

10/1 = -k * (100 - 25)

k = -10/75°C

After 4 minutes, dT/4 = 10/75 (100 - 25) = 10

dT = 40

Temperature after 4 minutes = 100 - 40 = 60°C

The temperature of a cup of coffee varies according to Newton's Law of Cooling, the temperature of the coffee after 4 minutes is approximately 67°C.

To tackle this problem, we can apply Newton's Law of Cooling's differential equation and solve it using variable separation.

dT/dt = -k(T - A)

At t = 0 (initial condition): T = 100°C

At t = 1 minute: T = 90°C

dT/dt = -k(T - A)

At t = 0: dT/dt = -k(100 - 25)

So,

-10 = -k(75)

k = 10/75

Separating variables and integrating, we have:

1/(T - A) dT = -k dt

∫(1/(T - A)) dT = ∫(-k) dt

ln|T - A| = -kt + C

ln|100 - 25| = 0 + C

ln|75| = C

So, the equation will be:

ln|T - A| = -kt + ln|75|

ln|(T - 25)/(75)| = -kt

Now,

ln|((T - 25)/(75))| = -(10/75)(4)

|((T - 25)/(75))| = [tex]e^{(-40/75)[/tex]

T - 25 = ± 75 *  [tex]e^{(-40/75)[/tex]

T = 25 ± 75 *  [tex]e^{(-40/75)[/tex]

T ≈ 25 ± 42.42

Therefore, the temperature of the coffee after 4 minutes is approximately:

T ≈ 25 + 42.42 = 67.42°C

Thus, the temperature of the coffee after 4 minutes is approximately 67°C.

For more details regarding Newton's Law of Cooling, visit:

https://brainly.com/question/30591664

#SPJ2

What is the correct definition of a circuit?

Answers

A circuit is a closed path that allows electricity to flow from one point to another. It may include various electrical components, such as transistors, resistors, and capacitors, but the flow is unimpeded by a gap or break in the circuit. A flashlight is an example of a basic circuit.

Hope this helps. Have a good day!

What do you need to do before you can make a hypothesis?

Answers

You need to identify the question and understand what it’s asking. Then you make your hypothesis (an educated guess) about what will happen.

An object on the surface of the earth weighs 90 lb. At two earth radii above the surface, It will welgh:
270 lb.
10 lb.
90 lb.
30 lb.

Answers

I have no explanation, but saw this pop up on a test paper and the answe was 10lb

A car accelerates from rest. It reaches a velocity of 25m/s in 10 seconds. What was the cars acceleration

Answers

Answer:

a = 2.5 m/s^2

Explanation:

u = 0

v = 25

t = 10

(using first eq. of motion)

a = (v - u) /t

a = (25 - 0) /10

a = 25/10

a = 2.5 m/s^2

a point charge q is held stationary at the origin, its electric potential of 2.8 x 10^4 V is measured at 1.1m away from the point charge. what is the magnitude of the point charge q

Answers

The magnitude of the point charge held stationary at the origin and at given electric potential is determined as 3.42 x 10⁻⁶ C.

Magnitude of the charge

The magnitude of the charge held stationary at the origin is calculated as follows;

V = kq/r

where;

k is Coulomb's constant = 9 x 10⁹ Nm²/C²q is the magnitude of the charge = ?r is the distance of separation = 1.1 m

Substitute the given parameters into the above equation and solve magnitude of the point charge.

kq = Vr

q = Vr/k

q = (2.8 x 10⁴ x 1.1)/(9 x 10⁹)

q = 3.42 x 10⁻⁶ C

Thus, the magnitude of the point charge held stationary at the origin and at given electric potential is determined as 3.42 x 10⁻⁶ C.

Learn more about electric potential here: https://brainly.com/question/26978411

will there be a mega tsunami like in the movie tidal wave from 2009?​

Answers

I really hope not but maybe it is possible
Maybe, hope not, ..hi

Which is the best reason Venus' temperature is approximately uniform, hot on both day and night sides?

plate tectonics

retrograde rotation

atmospheric convection

planetary differentiation

differential rotation

Answers

The main reason Venus has a "uniform" temperature is atmospheric convection.

What is atmospheric convection?

Atmospheric convection is a term to refer to the difference in temperature, in the atmospheric layer. In short, it refers to the movement of air bodies of different temperatures in the atmosphere of a planet.

In the case of Venus, atmospheric convection contributes to this planet's temperature uniformity because hot air is in constant contact with the planet's surface, preventing it from cooling.

Learn more about temperature in: https://brainly.com/question/7510619

if a metal block has as a volume of .035 mL, and a mass of 765.0 mg, what is the density of the block in g/mL?

Answers

Given parameters:

Volume of metal block = 0.035mL

Mass of block  = 765mg

Unknown:

Volume of metal block = ?

Solution:

Density is the mass per unit volume of a substance.

  Density  = [tex]\frac{mass}{volume}[/tex]

Mass is the amount of matter in a substance

Volume is space occupied by a substance

     Mass of the block in g;

                         765mg =    765 x 10⁻³ g

                                     = 0.765g

 Density = [tex]\frac{0.765}{0.035}[/tex]   = 21.86g/mL

The density of the metal block is 21.86g/mL

You have been hired by a "storm chaser" as an assistant. This individual loves to find locations at which tornadoes and violent lightning storms are occurring. While there, he takes photographs and makes electromagnetic measurements. You are on a chase with him to a lightning storm in Florida. He explains to you that a cloud layer and the ground can be considered as the plates of a capacitor that stores charge, with the ground being charged negatively. The capacitor continuously leaks charge due to the free charges in the air between the plates. In thunderclouds, however, various processes result in charge distributions that eventually lead to lightning, a phenomenon that delivers negative charge to the ground. Therefore, the lightning recharges the capacitor. Ahead of you is a cloud layer that the storm chaser measures to be of area 2.00 km2 and height 10 km above the ground. He then uses a special apparatus called a field mill to measure that the electric field under the cloud is 4.00 â 10^6 N/C.

He asks you to do a quick calculation of the charge on the cloud-ground capacitor (in C), so you can know what to expect if there is a bolt of lightning.

Answers

Answer:

The  value is  [tex]q =  70.8\ C[/tex]

Explanation:

From the question we are told that

   The  area is  [tex]A =  2.0 \ k m^2 = 2000000 \  m[/tex]

   The height is  [tex]h  =  10 \  km  =  10000 \  m[/tex]

    The  electric field is  [tex]E =  4.0*10^{6} \  N/C[/tex]

Generally the electric field is mathematically represented as

      [tex]E =  \frac{q}{A *  \epsilon_o }[/tex]

Here [tex]\epsilon_o }[/tex] is the permitivity of free space with value  

      [tex]\epsilon_o }   =  8.85 *10^{-12} \  N \ m^2 /C^2[/tex]

=>   [tex]4.0*10^{6} =  \frac{q}{2000000 *    8.85 *10^{-12} }[/tex]

=> [tex]q =  70.8\ C[/tex]

A golf ball is hit 36 m/s at an angle of 40° with the horizontal. What is the vertical component of the ball’s velocity?
A. 15 m/s
B.26.7 m/s
C. 23.1 m/s
D. 36 m/s

Answers

Answer:

ززث ع ثذآرثفاقآثہ تجفہجاءآڑجءبیجدءچءاءاڑڑشءڑدءحابڑءحبزیاڑچءازءچزیبزچدزچ،چدز،ڈزیجپا،جڈزیجڈیبزءفحدءڈحضغ دح دفھچءچدجءیچزءچددفحءدفءاڑحعخ حدھغچغھافءاڑاڑہشھدفڈچقڈ،شڈیچڑ

Cameron and Morgan are each holding a bar magnet with opposite poles facing each other. They walk in opposite directions until they stop feeling their magnet pull towards the other one What can they conclude about the distance between them when they stop feeling their magnets pull?

A. They are outside the magnetic field of their magnets.

B. The distance made the magnets' force stronger.

C. The magnetic field was weaker when they were close.

D. The magnetic fields are far enough apart to change direction.​

Answers

Answer:

a.

Explanation:

i did a quizz for it im sorry if im wrong

No No que no me ha dicho que ha sido el teléfono del teléfono y no se han dado la cara de vuelta

What does it mean to say that mass is conserved during a physical change​

Answers

Answer: When there is no change in chemical composition of a substance then it is known as physical change. When we say that mass is conserved during a physical change then it means that total mass of the substance or object will remain the same from beginning till the end

Answer:

Sample Response: When a physical change occurs, the mass of the substance is conserved. This means that the total mass of the substance remains the same from beginning to end. The physical properties of the substance, such as size and shape, may change, but the amount of matter in the substance does not change.

Explanation:

it is more difficult to climb a vertical staircasethan a slanted one​

Answers

Answer:

it's because of friction

Explanation:

In slanted one the friction will be less so it would be more difficult to climb

the density of gold is 19kg/cm³ find the volume of a) 38g b)0.095kg. solve this question and give explanation i will mark you as brainlist​

Answers

Answer:

a)  0.002 cm³

b) 0.005 cm³

Explanation:

density d = 19 kg/cm³

Given mass m, find volume V

The definition of density is

d = m/V

so V = m/d

a) m = 38 g = 0.038 kg

so V = 0.038/19 = 0.002 cm³

b) m = 0.095 kg

V = 0.095/19 = 0.005 cm³

Other Questions
Pina Corporation factors $268,100 of accounts receivable with Kathleen Battle Financing, Inc. on a with recourse basis. Kathleen Battle Financing will collect the receivables. The receivables records are transferred to Kathleen Battle Financing on August 15, 2020. Kathleen Battle Financing assesses a finance charge of 2% of the amount of accounts receivable and also reserves an amount equal to 4% of accounts receivable to cover probable adjustments. (b) Assume that the conditions are met for a transfer of receivables with recourse to be accounted for as a sale. Prepare the journal entry on August 15, 2020, for Pina to record the sale of receivables, assuming the recourse obligation has a fair value of $4,380. (If no entry is required, select "No Entry" for the account titles and enter 0 for the amounts. Credit account titles are automatically indented when the amount is entered. Do not indent manually.) Samuel is getting a degree from a university next May in finance. Is Samuel fulfilling a duty or a responsibility as a U.S. citizen? What pattern is there with regard to valence electrons, oxygen bonding ratio and electron configuration A soccer ball is kicked and travels 25 meters to the north in 2.5 seconds. At what velocity is the ball traveling?62.5 m north62.5 m/s north10 m10 m/s north marco needs to buy some cat food.At the nearest store, 3 bags of food cost 17.25$. How much would marco spend on 6 of cat food? What makes an amoeba different from a cougar? 2 factors that contribute to a detrimental relationship [ASAP] Choose the term to complete the sentence. A _____ is a drawing made up of lines without any surface color or shading.1. Raster2. Vector3. Rendering4. Wireframe Describe the process of transcription involve RNA polymerase. Write the equation in point slope form of the line that passes through the given point with the given slope (8.7,2.1);5.9 Which of David's paintings represent the murder of one of the Jacobin leaders? A. Death of Marat B. Oath of Horatii C. Napoleon in His Study at the Tuileries. Insert 2 sets of parentheses to make each sentence true: 2 x 14 9 17 14 = 7 The best and most accurate word choices to describe the experience of winning a race would be? How many more people voted to leave the Union than those who did not? whats 1 and 5\5 as an improper fraction In designing the organization:________. A) the initial design is usually complicated.B) poor design is a significant cause for business failure since the entrepreneur often performs all organization functions themselves.C) the entrepreneur easily transitions from a growing start-up to a growing, well-managed business.D) as the workload increases the organizational structure will contract. If you place a 39-foot ladder against the top of a building and the bottom of the ladder is 31 feet from the bottom of the building, how tall is the building? Round to the nearest tenth of a foot. Statistical sampling:_________. a. is typically less complicated than non-statistical sampling b. can be used in addition to testing specific items from a population c. should generally not be used for auditing engagementsd. can be used instead of testing specific items from a population Find the sum 4 3/82 1/8."(help me pls ASAP)" In First Steps, which theme is developed by Marias experiences on the planet?No matter how far one travels, one always misses home.For most people, exploring the unfamiliar is upsetting.Facing one's fears often leads to great discoveries.It is safest to think carefully before taking action.