A 1000-kg car comes to a stop without skidding. The car's brakes do 50,000 J of work to stop the car. Which of the following was the car's velocity when the brakes were initially applied?

Answer:

65 N

Explanation:

Assuming that the ball was at rest hence initial momentum = 0

Final momentum = mv = 1Kg × 13 ms-1 = 13 kgms-1

But

Ft= mv according to Newton's law

F= mv/t

F= 13kgms-1/0.2s

F= 65 N

Answer:

65 N

Explanation:

Given that :

Mass of ball = 1kg

Velocity = 13m/s

Time = 2 seconds

Using the relation :

Force = (mass * change in velocity) / time

The change in momentum of the ball :

Momentum = mass * change in velocity

Velocity change = (13 - 0) ; Given that initial velocity = 0 (at rest)

Momentum = 1kg * 13m/s

Momentum = 13 kgm/s

Therefore, the force, F equals;

F = change in momentum / time

F = 13kgm/s ÷ 0.2 s

Hence, Force, F = 65N

Answer:

The laws of physics which apply when you are at rest on the earth also apply when you are in any reference frame which is moving at a constant velocity with respect to the earth. For example, you can toss and catch a ball in a moving bus if the motion is in a straight line at constant speed.

Explanation:

Answer:

first lets do the anti parralel part of forces

we get 18. 25-15 =3.25 to north

then ww use phytagores theorem

3.25^2+4.75^2=c(resultant )

10.56+22.56=33.12

square root of 33.12 is 5.75

Answer:

d = 20.2 m

t = 2.02 s

Explanation:

Horizontal Motion

When an object is thrown horizontally with a speed v from a height h, it describes a curved path ruled by gravity until it hits the ground.

To calculate the time the object takes to hit the ground, we use the equation:

[tex]\displaystyle t=\sqrt{\frac{2h}{g}}[/tex]

Note the time does not depend on the initial speed.

The range or maximum horizontal distance traveled by the object can be calculated as follows:

[tex]\displaystyle d=v.t[/tex]

The man standing on the edge of the h=20 m cliff throws a rock with a horizontal speed of v=10 m/s.

The time taken by the rock to reach the ground is:

[tex]\displaystyle t=\sqrt{\frac{2*20}{9.8}}[/tex]

[tex]\displaystyle t=\sqrt{4.0816}[/tex]

t = 2.02 s

Now for the horizontal range:

[tex]\displaystyle d=10\cdot 2.02[/tex]

d = 20.2 m

Answer:The slope in the velocity-time graph represents the acceleration. The slope is defined as the ratio of change in y-axis to change in the x-axis. The slope is represented by the letter m and following is the general formula used for determining the slope:

Explanation:

Answer:

C, 400 N

Explanation:

Given parameters:

Mass of object  = 50kg

Acceleration  = 8m/s²

Unknown:

Amount of force  = ?

Solution:

According to Newton's second law of motion;

       Force  = m a

m is the mass

a is the acceleration

 Now insert the parameters and solve;

   Force  = 50  x  8  = 400N

Answer:

20m/s²

Explanation:

Given parameters:

Force  = 10000N

Mass  = 500kg

Unknown:

Acceleration  = ?

Solution:

According to Newton's second law of motion:

     Force  = mass x acceleration

Mass is the amount of matter in a substance

Acceleration is the rate of change of velocity with time

 Now insert the parameters and solve;

           10000 = 500 x acceleration

            Acceleration  = 20m/s²

Answer:

a) α = -65,2 rad/s².

b) t = 2,57 s.

Explanation:

a) La aceleración angular se puede calcular usando la siguiente ecuación:

[tex] \omega_{f}^{2} = \omega_{0}^{2} + 2\alpha \theta [/tex]

En donde:

[tex]\omega_{f}[/tex]: es la velocidad angular final =  2000 rpm = 209,4 rad/s

[tex]\omega_{0}[/tex]: es la velocidad angular inicial = 3600 rpm = 377,0 rad/s

α: es la aceleración angular=?

θ: es el desplazamiento o número de vueltas = 120 rev = 754,0 rad

Las conversiones de unidades se hicieron sabiendo que 1 revolución = 2π radianes y que 1 minuto = 60 segundos.  

Resolviendo la ecuación (1) para α, tenemos:

[tex]\alpha = \frac{\omega_{f}^{2} - \omega_{0}^{2}}{2\theta} = \frac{(209,4 rad/s)^{2} - (377,0 rad/s)^{2}}{2*754,0 rad} = -65,2 rad/s^{2}[/tex]  

Entonces, la aceleración angular es -65,2 rad/s². El signo negativo se debe a que el motor está desacelerando.  

b) El tiempo transcurrido se puede encontrar como sigue:

[tex] \omega_{f} = \omega_{0} + \alpha t [/tex]

Resolviendo para t, tenemos:

[tex]t = \frac{\omega_{f} - \omega_{0}}{\alpha} = \frac{209,4 rad/s - 377,0 rad/s}{-65,3 rad/s^{2}} = 2,57 s[/tex]

Por lo tanto, el tiempo transcurrido fue 2,57 s.

Espero que te sea de utilidad!

Answer:

Decorating. Because mirrors reflect light, they create an illusion of open space by doubling whatever is in a room. ...

Safety. People use mirrors and lenses for safety. ...

Vision. Eye doctors use lenses to correct vision. ...

Magnification and Science. ...

Energy and Affirmation Techniques. ...

Photography. ...

Answer:

100 Pa

Explanation:

650 ÷ 6.5 = 100 ( Pa )

[tex]\\ \sf\longmapsto Pressure=\dfrac{Force}{Area}[/tex]

[tex]\\ \sf\longmapsto Pressure=\dfrac{650}{6.5}[/tex]

[tex]\\ \sf\longmapsto Pressure=100Pa[/tex]

Answer:

The value is [tex]\phi = 70 N\dot m^2 / C[/tex]

Explanation:

From the question we are told that

     The area vector is  [tex]\vec A = (10i + 8j) \ m^2[/tex]

     The  electric field is  [tex]E = 7 i \ N/C[/tex]

Generally the flux is  mathematically represented as  

        [tex]\phi = \vec E * \vec A[/tex]

=>      [tex]\phi = 7i * ( 10 \ i + 8 \ j )[/tex]

=>       [tex]\phi = (7 * 10 )\ i[/tex]  

Note  [tex]i \cdot j = 0[/tex]

=>      [tex]\phi = 70 N\dot m^2 / C[/tex]

Answer:

1) True

2) None of the above

Explanation:

Q # 1:

Weight is actually the gravitational force or force of gravity. So, it's true.

Q # 2:

None of above because force of gravity can not be negative. In order to have a negative weight, the body has to be "repelled" by gravity.

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer:

Time taken 4 hrs. 38 minutes

Explanation:

As speed = distance/time interval

So time taken = 4.38

speed=distance/time

we know the speed and we know the distance so we can calculate the time

120km/h=525km/time

time=525km/120km/h=4.375hours or 4 hours and 22 minutes and 30 seconds

Answer:

because the light is refracted and slowed down to make us see the color "green"  and the things we see..like paper..the color "green" A white sheet of paper reflects almost all the light that falls on it. It reflects white light because it can reflect all the colors of the spectrum that comprise white light. If red light only is shone onto a white page, the red light is reflected. If the green light is shone onto the page, the green light is reflected.

Explanation:

hope this helps?

Answer:

the wave length that are reflected  determine the color  that an object appears  to the human eye. for example,the leaves appear green because  they reflect green light and absorb light of other  wavelengths.This means that  the light passes through the material rather than being reflected by it.

Explanation:

Answer:

Explanation:

The density of a substance can be found by using the formula

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

From the question we have

[tex]density = \frac{4000}{2} = 2000 \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

Explanation:

he SI rests on a foundation of seven (7) defining constants: the cesium hyperfine splitting frequency, the speed of light in vacuum, the Planck constant, the elementary charge (i.e. the charge on a proton), the Boltzmann constant, the Avogadro constant, and the luminous efficacy of a specified monochromatic source. Definitions of all seven (7) SI base units are expressed using an explicit-constant formulation and experimentally realized using a specific mises en pratique (practical technique).

The seven SI base units, which are comprised of:

Length - meter (m)

Time - second (s)

Amount of substance - mole (mole)

Electric current - ampere (A)

Temperature - kelvin (K)

Luminous intensity - candela (cd)

Mass - kilogram (kg)

The International System of Units (SI), commonly known as the metric system, is the international standard for measurement. The International Treaty of the Meter was signed in Paris on May 20, 1875 by seventeen countries, including the United States and is now celebrated around the globe as World Metrology Day. NIST provides official U.S. representation in the various international bodies established by the Meter Convention: CGPM - General Conference on Weights and Measures; CIPM - International Committee for Weights and Measures; and BIPM - The International Bureau of Weights and Measures.

The SI is made up of 7 base units that define the 22 derived units with special names and symbols. The SI plays an essential role in international commerce and is commonly used in scientific and technological research and development. Learn more about the SI in NIST SP 330 and SP 811.

Resources for Students and Teachers

Redefining the SI – In November 2018, the world’s measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature. The changes became effective on World Metrology Day, May 20, 2019. (NIST)

Learn more about the Road to the Revised SI. Learn more about the SI Redefinition.(NIST)

The Last Artifact documentary and companion Grade 5 to 12 educational resources, which document the work that went on behind the scenes to modernize the International System of Units (SI). (Montana PBS)

NIST SP 1247 SI Base Units Relationships Poster – a colorful poster illustrating the relationships of the International System of Units (SI) derived units with special names and symbols and the seven traditional base units. (NIST)

Metric Trivia Quiz – How much do you know about the metric system (SI)? Try the NIST Metric Trivia Quiz online or use the Alexa skill to test your knowledge and be on your way to thinking metric! (NIST)

SI Education and Training – Explore NIST metric system education resources that build SI measurement system familiarity and fluency. (NIST)

Kids Education Resources. (NIST)

Busting Myths about the Metric System. (NIST Taking Measure Blog)

Resources

Becoming Familiar with SI

Everyday Estimation

Metrication FAQs

Prefixes

SI Publications

Understanding Metric

Writing with Metric Units

Answer:

International System of Units??

Answer:

4.28 s

Explanation:

after two seconds (2 s) His friends is

d = 3.5 m/s x 2 s = 7 meter ahead.

in this state, a bicylist start from initial velocity vo = 0 m/s and accelerat 2.4 m/s²

then, when bicylist reach his friend

t friend = t bicyclist = t

d bicylist = d friend + d

-------

d friend = 3.5 . t

d bicylist = vo . t + ½ a t²

d friend + d = vo . t + ½ a t²

3.5 t + 7 = 0 . t + ½ . 2.4 . t²

3.5 t + 7 = 1.2 t²

0 = 1.2 t² - 3.5 t - 7

t = -1.363 and t = 4.28

take the positive one

Answer:

A theory

Explanation:

No, the person who answered above is incorrect. I just took the assessment and I can guarantee you the answer is "a theory".

-Lexi

Answer:

a) [tex] F_{T} = 40 N [/tex]

b) The object will move in the east direction

Explanation:

a) The net force is given by the vector sum of the given forces:

[tex] F_{T} = F_{1} + F_{2} [/tex]

Where:

F₁ = the west force = 20 N

F₂ = the est force = 60 N  

Taking the east direction as the positive direction we have:

[tex] F_{T} = -20 N + 60 N = 40 N [/tex]

Hence, the net force is 40 N.

b) Since the east force is greater than the west force, the object will move to the east.

I hope it helps you!  

Answer:

Explanation:

A rise in temperature increases the kinetic energy and speed of particles; it does not weaken the forces between them. The particles in solids vibrate about fixed positions; even at very low temperatures. Individual particles in liquids and gases have no fixed positions and move chaotically.

Answer:

[tex]a = 0.894\ m/s^2[/tex]

Explanation:

Motion with Constant Acceleration

A body moves with constant acceleration when the speed changes uniformly in time. The equation used to find the final speed vf is

[tex]v_f=v_o+at[/tex]

Where vo is the initial speed, a is the acceleration, and t is the time.

The cyclist has an initial speed of vo=10 miles/hour and ends up at vf=20 miles/hour in t=5 seconds.

Both speeds are given in miles/hour and we must convert it to m/s:

1 mile/hour = 0.44704 m/s

10 mile/hour = 4.47 m/s

20 mile/hour = 8.94 m/s

The acceleration is calculated by solving for a:

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

[tex]\displaystyle a=\frac{8.94-4.47}{5}[/tex]

[tex]a = 0.894\ m/s^2[/tex]

Answer:

Option B. 3660000 J

Explanation:

At the sea level, we'll assume that the height is 0 m. Hence, the potential energy at the sea level is zero.

Next, we shall determine the potential energy at a height of 366 m above the sea level. This can be obtained as follow:

Mass (m) = 1000 kg

Acceleration due to gravity (g) = 10 m/s²

Height (h) = 366 m

Potential energy (PE) =?

PE = mgh

PE = 1000 × 10 × 366

PE = 3660000 J

From the calculations made above, we can see clearly that the potential energy of the car at a height of 366 m above sea level is 3660000 J.

Hence, the potential energy of the car increases from 0 at the sea level to 3660000 J at 366 m above the sea level.

Answer:

The scale will read less than 700 N

Explanation:

Given;

normal weight of the person, W = 700 N

The upward acceleration of the elevator is given by Newton's second law of motion;

F = ma

Also, the weight of the person, W = mg

Net force on the person when the elevator accelerates upward is given as;

R = ma + mg

When the elevator slows down at a steady rate, then net force on the person is given as;

R = mg - ma

R = m(g - a), this net force on the person is also the reading of the scale.

Thus, the scale will read less than 700 N.

Answer: The answer is less than 700 N

Answer:

The white car will cover the most distance every second.

Explanation:

The formula for the uniform speed of an object is given as follows:

[tex]s = vt[/tex]

where,

s = distance covered by the object

v = speed of the object

t = time required

Now, if we assume time to be  constant at 1 s. Then the distance covered by each car will be directly proportional to the speed of the car. Hence, the car with the greatest speed will travel the greatest distance in 1 second.

We, have:

Speed of white car > Speed of red car > Speed of green car

Therefore, the white car will cover the most distance every second.

Answer:

A system is a group of interrelated interacting, or interdependent parts that for a complex whole. A system is a group of interrelated interacting, or interdependent parts that for a complex whole.

Explanation: Hope this helps ;)

Answer:

D. Downshift to allow you to turn more sharply

D. downshift to allow you to turn more sharply

The purpose of "downshifting", or shifting the transmission down from a higher gear to a lower gear, is so that a driver can accelerate their car as fast as possible when exiting a corner that they had to slow down for.

The reason for ensuring your downshift is completed before turning into the corner is because letting the clutch out and engaging a lower gear while turning can cause the car to spin.

Two special conditions where you should downshift

Before Starting Down a Hill.

Slow down and shift down to a speed that you can control without using the brakes hard. Otherwise the brakes can overheat and lose their braking power.

Before Entering a Curve.

Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning. It also allows you speed up as soon as you are out of the curve.

Therefore,

In the middle of a turn, you should downshift to allow you to turn more sharply .

Learn more about Downshift here:

https://brainly.com/question/10600958

#SPJ2

Answer:

Solution given:

Wight [W]=500N

gravity [g]=10m/s²

mass[m]=?

we have

W=mg

500=m*10

m=500/10

m=50kg

the mass of the truck is 50kg.