Can someone help me with this physics question? I don't know which answer is correct.

Answer:

It can rotate in any direction. The sign of the angular acceleration depends on how you set the reference system, it can be both negative or positive.

Answer:

[tex]0.6\; \rm m\cdot s^{-1}[/tex], assuming that drag of the water on the log is negligible.

Explanation:

The momentum [tex]p[/tex] of an object is equal to the product of mass [tex]m[/tex] and velocity [tex]v[/tex]. That is, [tex]p = m\, v[/tex].

If the drag of water on the log is negligible, momentum of the beaver and the log, combined, would be preserved.

The momentum of the beaver and the log, combined, was initially [tex]0\; \rm kg\cdot m \cdot s^{-1}[/tex].

The momentum of the beaver right after the dive would be [tex]7.5 \; {\rm kg} \times 4\; {\rm m \cdot s^{-1}} = 30\; {\rm kg \cdot m \cdot s^{-1}}[/tex].

The sum of the momentum of the beaver and the log is conserved and should continue to be [tex]0\; {\rm kg\cdot m \cdot s^{-1}}[/tex] even after the dive. Since the momentum of the beaver is [tex]30\; {\rm kg \cdot m \cdot s^{-1}[/tex] after the dive, the momentum of the log should become [tex](-30)\; {\rm kg \cdot m \cdot s^{-1}}[/tex].

Since the mass of the log is [tex]50\; {\rm kg}[/tex], the new velocity of this log would be:

[tex]\begin{aligned}v &= \frac{p}{m} \\ &= \frac{(-30)\; {\rm kg \cdot m \cdot s^{-1}}}{50\; {\rm kg}} \\ &= (-0.6)\; {\rm m \cdot s^{-1}}\end{aligned}[/tex].

(The new velocity of the log is negative because the log would be moving away from the beaver.)

The speed of an object is the magnitude of velocity. For this log, a velocity of [tex](-0.6)\; {\rm m \cdot s^{-1}}[/tex] would correspond to a speed of [tex]|(-0.6)\; {\rm m \cdot s^{-1}| = 0.6\; {\rm m \cdot s^{-1}[/tex].

Answer:

0.9m/s^2 (yours is 0.87, so choose that)

Explanation:

formula for centripetal acceleration:

v^2/r

to find v, we know that f=1/90s, and r=180m.

v=(2pir)/T

v=(2pi(180))/90

v=12.6m/s

now plug into a=v^2/r

a=(12.6)^2/180

a=0.9m/s^2

Answer:

The first one.

If the road becomes wet or crowded, you should ___ slow down and increase your following distance_

The safe distance between vehicles traveling in column specified by the command in light of safety requirements

The slower speed will help you save gas and avoid potential accidents. You can easily eliminate chances of rear end collision by maintaining a safe distance between your car and the vehicles ahead.

hence , a) slow down and increase your following distance is a correct option

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Answer:

This is because some kinetic energy had been transferred to something else.

Explanation:

An inelastic collision is a collision in which there is a loss of kinetic energy. While momentum of the system is conserved in an inelastic collision, kinetic energy is not.

Hi there!

a.

The equation for centripetal acceleration is as follows:

[tex]\large\boxed{a_c = \frac{v^2}{r}}}[/tex]

Plug in the given values to solve:

[tex]\large\boxed{a_c = \frac{(65)^2}{75} = 56.33 m/s^2}[/tex]

b.

According to Newton's Second Law:

[tex]\large\boxed{\Sigma F = ma}}[/tex]

The acceleration is v²/r, so the net force is:

[tex]\large\boxed{\Sigma F = m(\frac{v^2}{r})}}[/tex]

Multiply by the given mass:

[tex]\large\boxed{\Sigma F = 700(56.33) = 39433.33 N}}[/tex]

c.

There is NO net force in the vertical direction since the object is NOT accelerating in the vertical direction (normal force and weight cancel).

Thus, the ONLY net force experienced by the object is in the horizontal direction and is EQUAL to the centripetal force.

The half-life of the given isotope will be 10 days, if after 30 days only 31.25 grams are remaining from a sample of 250 grams of the sample size taken in the beginning.

The Half-life is the time which is required for a quantity to reduce the content to half of the amount present as its initial value. The term is used in nuclear physics to describe how quickly an unstable atom undergo radioactive decay or how long does stable atoms survive. The term is also used generally to characterize any type of exponential decay.

The half-life of the isotope can be calculated by the formula:

FR = 0.5n

FR = Fraction Remaining = 31.25 g / 250.0 g = 0.1250

n = number of half lives elapsed = ?

0.125 = 0.5n

log 0.125 = n log 0.5

-0.9031 = -0.3010 n

n = 3.000 half lives have elapsed

3 half lives = 30 days

1 half live = 10 days

Therefore, the half-life of the isotope will be 10 days.

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Answer:

papi sus

Explanation:

Explanation:

it's mean hI small little cute baby girl ...

Answer:

the wave is carrying more energy

Explanation:

trust me broski

Answer:

a

Explanation:

Answer:

So as two objects are separated from each other, the force of gravitational attraction between them also decreases. If the separation distance between two objects is doubled (increased by a factor of 2), then the force of gravitational attraction is decreased by a factor of 4 (2 raised to the second power).

Explanation:

hope his helps

Answer:

Option C is the correct answer

Explanation:

Distance travelled by car during reaction time

[tex]=15\times0.4\\\\=6m[/tex]

The car stopped before hitting the animal by [tex]1 m[/tex]

Distance travelled during deceleration is [tex]21-6-1=14m[/tex]

Hence by [tex]v^2=u^2+2as[/tex]

We have

[tex]0^2=15^2+2 \cdot a \cdot 14\\\\a=\frac{-225}{28} \\\\=-8.03m/s^2[/tex]

Option C is the correct answer

Distance traveled during reaction time

Total distance

[tex]\\ \sf\longmapsto v^2-u^2=2as[/tex]

[tex]\\ \sf\longmapsto -(15)^2=2(14)a[/tex]

[tex]\\ \sf\longmapsto -225=28a[/tex]

[tex]\\ \sf\longmapsto a=-8.0m/s^2[/tex]

The displacement of  the plane during the acceleration is equal to 80.89 meters.

Given the following data:

To determine the displacement of  the plane during the acceleration, we would use the third equation of motion;

[tex]V^2 = U^2 + 2aS[/tex]

Where:

Substituting the given parameters into the formula, we have;

[tex]40^2 =12^2 + 2(9)S\\\\1600=144+18S\\\\18S=1600-144\\\\18S=1456\\\\S=\frac{1456}{18}[/tex]

Displacement, S = 80.89 meters.

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When traveling with average speed 40 km/h, the car would cover a distance of 80 km in time t such that

40 km/h = (80 km) / t   ⇒   t = 2 h

so the total travel time is 2 h + 3 h = 5 h.

Average speed is defined as the total distance traveled divided by the time it took to cover that distance. So if the overall average speed was 30 km/h, then

30 km/h = (80 km + x) / (5 h)   ⇒   x = 70 km

where x is the distance traveled in the last 3 h of the trip.

Then the total displacement of the car is 80 km + 70 km = 150 km.

To solve the problem it is necessary to apply the concepts of Torque and equilibrium.

The Torque is defined as:

Where

F= Force

d = Distance

In this particular case, the force is caused by the weight of both children.

In turn, when there is equilibrium, the two torques must be equal therefore

Replacing with our values

Re-arrange to find  

Therefore the distance that the second kid should sit to balance the see-saw is 1.8m from the pivot.

Answer:

Answer: B. Explanation: For an object to accelerate the force on it must be increased. According to Newton's second law of motion.

Explanation:

I do Accelerate to good luck

Newton's second law and the kinematic relations allow to find the results for the questions about forces and the movement of the block are:

    B) the force applied to maintain the system is equilibrium is: F = 0.39 N with an angle of tea = 180º

    C) The maximum force is: F = 24 N

    D) The time to stop the block is: t = 25 s

Newton's second law establishes a relationship between the net force, the mass, and the acceleration of the body. In the special case that the acceleration is zero it is called the equilibrium condition.

B) They indicate a diagram of forces on the block, let's look for the components of the force that the block maintains with zero acceleration, in the attached we have a free-body diagram including the force applied to keep the system in equilibrium.

x-axis

      -10 + 12 sin 60 + Fₓ = 0

        Fₓ = 10- 12 sin 60 = -0.39 N

y-axis

       12 cos 60 - 6 + F_y = 0

        F_y = 6 - 12 cos 60 = 0 N

We can give the result of the force in two ways:

Let's use Pythagoras' theorem to find the modulus.

       [tex]F = \sqrt{F_x^2 + F_y^2 } \\F = \sqrt{0.39^2 +0^2}[/tex]  

       F = 0.39N

We use trigonometry for the angle.

       [tex]tan \theta = \frac{F_y}{F_x}[/tex]

       tan θ=  0º

The component of the force is negative therefore this angle is in the second quadrant, to measure the angle from the positive side of the x axis in a counterclockwise direction.

        θ = 180 + θ'

        θ = 180 + 0

        θ = 180º

C) if the three forces can be moved and the maximum force occurs when they are all linear.

          10+ 6 + 6 + F = 0

          F = -24 N

D) if we maintain this force and eliminate the other three, the block stops, let's look for its acceleration.

          [tex]a = \frac{F}{m}[/tex]  

          a = [tex]\frac{24}{6}[/tex]  

         a =  4 m / s²

The acceleration is in the opposite direction of the initial velocity of the block v₀ = -100 m / s

If we use kinematic relations.

        v = v₀ - a t

Final velocity when stopped is zero

         t = [tex]\frac{0-v_o}{a}[/tex]

         t = 100/4

         t = 25 s

In conclusion using Newton's second law and the kinematics relations we can find the results for the questions about the forces and the motion of the block are:

    B) the force applied to maintain the system is equilibrium is: F = 0.39 N with an angle of tea = 180º

    C) The maximum force is: F = 24 N

    D) The time to stop the block is: t = 25 s

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Answer:

Explanation:

Do you mean "made" as in the element itself, or "made" as it is extracted from the Earth and refined.

====

The elements originate in the stars.  The fusion reactions in Earth's sun fuse hydrogen and helium atoms to make elements, up to iron.  Larger stars and powerful explosions such as supernova create the larger elements.  Humans, with the use of particle accelerators make even larger elements, nearly all of which are unstable and decay rapidly into smaller elements.  But their creation does offer the perk of naming rights if you can prove it was created, and don't pick a clearly untenable name.

The Fe in stardust from the sun collects in clumps via gravitational forces and, via meteorites, is carried to Earth.  This is the major source for pure iron on the Earth.

Iron has chemical properties that lead to it reacting with other substances (e.g., oxygen) and then becoming concentrated in deposits as a variety of salts  in the Earth's crust, as a result of natural processes.  These deposits are mined and the rock is heated to separate and purify the iron metal.

B 10,000 - 30,000 K Blue-white stars

A 7,500 - 10,000 K White stars

F 6,000 - 7,500 K Yellow-white stars

G 5,000 - 6,000 K Yellow stars (like the Sun)

The lowest temperature stars are red while the hottest stars are blue. Astronomers are able to measure the temperatures of the surfaces of stars by comparing their spectra to the spectrum of a black body.

Answer:

This is what the Ecological Footprint does: It measures the biologically productive area needed to provide for everything that people demand from nature: fruits and vegetables, meat, fish, wood, cotton and other fibres, as well as absorption of carbon dioxide from fossil fuel burning and space for buildings and roads.

Why it's useful:

Ecological footprint (EF), measure of the demands made by a person or group of people on global natural resources. It has become one of the most widely used measures of humanity’s effect upon the environment and has been used to highlight both the apparent unsustainability of current practices and the inequalities in resource consumption between and within countries.

Answer:

60n would be the needed force

The force needed to push a box weighing 30 N up a ramp that has an ideal mechanical advantage of 3 is equal to 10 N.

The mechanical advantage can be described as the ratio of the input force to the output force. The mechanical advantage of any machine can be determined by the ratio of the forces involved to do the work.

The ratio of the resistance force to the effort is called the actual mechanical advantage which will be comparatively less. The efficiency of a machine is always determined by equating the ratio of its output to its input.

The efficiency of the machine is equal to the ratio of the actual mechanical advantage (M.A.) and theoretical mechanical advantage. Mechanical advantage can be defined as the force produced by a machine to the force applied to it.

Given the load = 30 N and the ideal mechanical advantage = 3

Mechanical advantage = Load/ Effort

Input force or effort = Load/ M.A.

Force = 30/3

Input Force = 10 N

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Answer:

acid rain corrodes a monument. d.

Explanation:it only makes sense because its doing something to a physical object.and the other ones aren't.

The fastest time trial for the first quarter checkpoint is 2.02 s.

The slowest time trial for the first quarter checkpoint is 2.7 s.

The range of the times measured for the checkpoint is 0.68 s.

The given parameters;

The fastest time trial for the first quarter checkpoint is the least measured time value.

fastest time trial = least time measured

fastest time trial =  2.02 s

The slowest time trial for the first quarter checkpoint is the highest measured time value.

slowest time trial = 2.7 s

The range of the times measured for the checkpoint is difference between the fastest time and slowest time.

Range = fastest time - slowest time

Range = 2.7 - 2.02

Range = 0.68 s

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Answer:

2.02, 2.15, 0.13

Explanation:

A 2-column table with 5 rows. The first column has entries empty, time of trial number 1 (seconds), time of trial number 2 (seconds), time of trial number 3 (seconds), average time (seconds). The second column labeled one quarter checkpoint has entries 2.15, 2.05, 2.02, 2.07.

Use the table to answer the questions.

What is the fastest time trial for the first quarter checkpoint?

2.02

seconds

What is the slowest time trial for the first quarter checkpoint?

2.15 seconds

What is the range of times measured for this checkpoint?

0.13 seconds

Range be R and height be h

[tex]\boxed{\sf R=\dfrac{u^2sin2\theta}{g}}[/tex]

[tex]\boxed{\sf h=\dfrac{u^2sin^2\theta}{2g}}[/tex]

u=initial velocity

theta is angle of projection.

g=acceleration due to gravity

ATQ

[tex]\\ \sf\longmapsto R=2h[/tex]

[tex]\\ \sf\longmapsto \dfrac{u^2sin2\theta}{g}=\dfrac{2u^2sin^2\theta}{2g}[/tex]

Cancelling required ones

[tex]\\ \sf\longmapsto sin^2\theta=sin2\theta[/tex]

sin2O=2sinOcosO

[tex]\\ \sf\longmapsto sin^2\theta=2sin\theta cos\theta [/tex]

[tex]\\ \sf\longmapsto \dfrac{sin^2\theta}{sin\theta cos\theta=2[/tex]

[tex]\\ \sf\longmapsto \dfrac{sin\theta}{cos\theta}=2[/tex]

[tex]\\ \sf\longmapsto tan\theta=2[/tex]

[tex]\\ \sf\longmapsto \theta=tan^{-1}(2)[/tex]

[tex]\\ \sf\longmapsto \theta=63.4°[/tex]

Done

Option B is correct

2.1 kg of sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample. Option D is correct.

Mass is the quantity of the substance in the body or object. The SI unit of mass is Kilogram.

There are other units of measure,

First convert kg to gram,

Since, 1 Kg = 1000 g

2.1 kg = grams of sample

So,

Do the cross multiplication,

[tex]\rm mass\ of\ sample = \dfrac {2.1\ kg \times 1000\ g }{ 1 kg}\\\\\rm mass\ of\ sample =2100 g[/tex]

Now, convert 2100 g to nano-grams

Since, 1 g = 1 x 10⁹ ng

2100 g = ng of sample

So,

Do the cross multiplication,

[tex]\rm mass\ of\ sample = \dfrac {2100 g \times 1 \times 10^9 ng }{1\ g}\\\\\rm mass\ of\ sample = 2.1 \times 10^1^2 ng[/tex]

Therefore, 2.1 kg of  sodium bicarbonate is equal to the 2.1 x 10¹² ng of sample.

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