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3 years ago

7

A freight car moves along a friction less level railroad track at constant speed. The car is open on top. A large load of coal i

s suddenly dumped into the car. What happens to the velocity of the car?

1 answer:

maxonik [38]3 years ago

8 0

Answer:

The velocity of the freight car decreases.

Explanation:

This question is answered by the conservation of momentum principle.

When the freight car is moving at a certain speed, it has a constant momentum.

We will call this M1.

The equation for M1 will be:

M1 = Mass * Speed

Now when the coal is dumped into the freight car, the Mass increases.

Since conservation of momentum states that the momentum will remain the same. We have:

M1 = (Mass of freight + Mass of coal) * Speed

Since M1 is constant, if the mass increases, the speed had to decrease to keep the equation true.

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If a fertilized egg cannot reach the uterus, what is the most likely result?

murzikaleks [220]

D. A fetus will develop in the fallopian tube.

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3 years ago

Read 2 more answers

The positions of four objects as a function of time are shown

KengaRu [80]

There is no movement in line C and the greatest velocity occurs at line D. The answers are:

1. 0.5 m/s

2. 0.25 m/s

3. 14m and -2m

4. -1 m/s

<h3>What is Position - time Graph ?</h3>

Position time graph is the graph of distance or displacement against time. The slope of the graph is velocity.

The given positions of four objects as a function of time are shown

on the graph to the right.

1.) The velocity of object A will be the slope m of the line A.

Slope m = Δx / Δt

m = (4 - 0) / (8 - 0)

m = 4 / 8

m = 0.5 m/s

Velocity at A = 0.5 m/s

2.) The average velocity of object B will be the slope m of the line B.

Slope m = Δx / Δt

m = (6 - 4) / (8 - 0)

m = 2 / 8

m = 0.25 m/s

The average velocity of object B is 0.25s

3.) The object moved a total distance during the first eight seconds will be 4m for A, 2m for B, and 8m for D

Total distance = 4 + 2 + 8 = 14m

It’s net displacement during the same time will be 2. That is,

Displacement = 8 - 6 = -2m

4.) The greatest speed occurred at line D. The velocity of the object moving at the greatest speed will be the slope of the line D

V = -Δx / Δt

V = -8/8

V = -1 m/s

Therefore, there is no movement in line C and the greatest velocity occurs at line D.

Learn more about velocity time graph here :brainly.com/question/769606

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6 0

1 year ago

Please help <br>problems 2a.,2b.,3a.,and 3b.

Darina [25.2K]

Answer:

2a) x = 32 [mil/h]; 2b) t = 0.5[h]; 3a) t = 2.5 [h]; 3b) x = 185[mil]

Explanation:

2a)

We can solve this problem by using the kinematics equation, which relates speed to time and displacement.

$v=\frac{x}{t} \\v=velocity [\frac{mil}{h} ] = 32 [\frac{mil}{h}] \\t=time = 1 [h]\\x=v*t\\x=32[\frac{mil}{h} ]*1[h]\\x=32[mil}$

2b)

We can solve this problem by using the kinematics equation, which relates speed to time and displacement.

$v=\frac{x}{t} \\t=\frac{x}{v} \\t=\frac{420}{840}\\ t=0.5[h]$

3a)

We can solve this problem by using the kinematics equation, which relates speed to time and displacement.

$v=\frac{x}{t} \\t=\frac{x}{v} \\t=\frac{35}{14}\\ t=2.5[h]$

3b)

We can solve this problem by using the kinematics equation, which relates speed to time and displacement.

$v=\frac{x}{t} \\v=velocity [\frac{mil}{h} ] = 74 [\frac{mil}{h}] \\t=time = 2.5 [h]\\x=v*t\\x=74[\frac{mil}{h} ]*2.5[h]\\x=185[mil}$

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3 years ago

Hãy nêu sự tương tự giữa công của lực điện trong trường hợp này với công của trọng lực.

statuscvo [17]

Answer:

tốt ý bạn là gì?

Explanation:

6 0

2 years ago

A small block of mass 20.0 grams is moving to the right on a horizontal frictionless surface with a speed of 0.68 m/s. The block

Usimov [2.4K]

Answer:

a) $v'=-0.227\ m.s^{-1}$

b) $v=1.36\ m.s^{-1}$

Explanation:

Given:

mass of the lighter block, $m'=0.02\kg$

velocity of the lighter block, $u'=0.68\ m.s^{-1}$

mass of the heavier block, $m=0.04\ kg$

velocity of the heavier block, $u=0\ m.s^{-1}$

a)

Using conservation of linear momentum:

$m'.u'+m.u=m'.v'+m.v$

where:

$v'=$ final velocity of the lighter block

$v=$ final velocity of the heavier block

$m'.u'=m'.v'+m.v$

$m'(u'-v')=m.v$ ........................(1)

Since kinetic energy is conserved in elastic collision:

$\frac{1}{2}m'.u'^2=\frac{1}{2}m'.v'^2+\frac{1}{2}m.v^2$

$m'(u'^2-v'^2)=m.v^2$

$m'(u'-v')(u'+v')= m.v^2$

divide the above equation by eq. (1)

$v=u'+v'$ .............................(2)

now we substitute the value of v from eq. (2) in eq. (1)

$m'(u'-v')=m(u'+v')$

$\frac{m'+m}{m'-m} =\frac{u'}{v'}$

$\frac{0.02+0.04}{0.02-0.04} =\frac{0.68}{v'}$

$v'=-0.227\ m.s^{-1}$ (negative sign denotes that the direction is towards left)

b)

now we substitute the value of v' from eq. (2) in eq. (1)

$m'(u'-v+u')=m.v$

$2m'.u'=(m-m')v$

$2\times 0.02\times 0.68=(0.04-0.02)\times v$

$v=1.36\ m.s^{-1}$

6 0

3 years ago