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Romashka [77]
3 years ago
15

A toy car has an initial acceleration of 2 m/s" across a horizontal surface after it is released from rest. After the car travel

s for a timet
consisting of only the car an open system or a closed system, and why?
Open system because the acceleration of the car is not constant.
Open system, because an external force is applied to the car that causes it to accelerate.
Closed system, because the speed of the car is as expected in the case where an object has uniform acceleration for a timet
Closed system because mechanical energy was not removed from the system as a result of a net force
Rie
B
7:53 PM
12/11/2019
Physics
2 answers:
Ganezh [65]3 years ago
3 0

Answer:

Closed system, because the speed of the car is as expected in the case where an object has uniform acceleration for a time t

Explanation:

Here in the question it is mentioned that a toy car has an initial acceleration of 2m/s²  across a horizontal surface so we can say that it is acted upon by an external force

Assuming that the acceleration is constant and the reason for this assumption is there at the last

The major difference between an open system and closed system is in case of open system there will be transfer of matter and in case of closed system there will be no change in matter of the system

If acceleration is constant in case of closed system we can expect the speed of the car after a time t by using the formula

  s = u×t + 0·5×a×t²

where s is the distance travelled

t is the time taken to travel that distance

u is the initial velocity

a is the acceleration of that system

But in case of open system as there will be a change of mass there will be a change in velocity of the system so in this case we cannot expect the speed of the car after a time t

And if the acceleration is not constant then we cannot say that the toy car is an open system or closed system, that is why we are assuming that the acceleration of the toy car is constant

ycow [4]3 years ago
3 0

Answer:

Open system, because an external force is applied to the car that causes it to accelerate.

Explanation:

A system is a space in the universe that is separated for study. It can be closed or open. A closed system is systems that aren't affected by external forces, and also didn't change the energy of the surroundings. An open system, on the other hand, is affected by external forces or change energy with the surroundings.

In this case, if only the toy car is the system, we can assume it as an open system, because an external force had to be done to it, so it could be in movement. In other words, an external force is applied to the car that causes it to accelerate.

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An object is five focal lengths from a concave mirror.how do the object and image heights compare?
enot [183]

An object distance is presented as s = 5f and we know that the mirror equation relates the image distance to the object distance and the focal length.

The mirror equation is 1/f = 1/s + 1/s’ where the variable f stands for the focal length of the mirror. Variable (s) represents the distance between the mirror surface and the object and the variable <span>(s’) represents the distance between the mirror surface and the image. </span>

In addition, a concave mirror will have a positive focal length (f) and a convex mirror will have a negative focal length (f).

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7 0
3 years ago
In midair an M = 145 kg bomb explodes into two pieces of m1 = 115 kg and another, respectively. Before the explosion, the bomb w
Daniel [21]

Answer:

v_2=-133.17m/s, the minus meaning west.

Explanation:

We know that linear momentum must be conserved, so it will be the same before (p_i) and after (p_f) the explosion. We will take the east direction as positive.

Before the explosion we have p_i=m_iv_i=Mv_i.

After the explosion we have pieces 1 and 2, so p_f=m_1v_1+m_2v_2.

These equations must be vectorial but since we look at the instants before and after the explosions and the bomb fragments in only 2 pieces the problem can be simplified in one dimension with direction east-west.

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Mv_i=m_1v_1+m_2v_2

Which means (since we want v_2 and M=m_1+m_2):

v_2=\frac{Mv_i-m_1v_1}{m_2}=\frac{Mv_i-m_1v_1}{M-m_1}

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5 0
3 years ago
Select the situation for which the torque is the smallest.
alina1380 [7]

Answer:

e. The torque is the same for all cases.

Explanation:

The formula for torque is:

τ = Fr

where,

τ = Torque

F = Force = Weight (in this case) = mg

r = perpendicular distance between force an axis of rotation

Therefore,

τ = mgr

a)

Here,

m = 200 kg

r = 2.5 m

Therefore,

τ = (200 kg)(9.8 m/s²)(2.5 m)

<u>τ = 4900 N.m</u>

<u></u>

b)

Here,

m = 20 kg

r = 25 m

Therefore,

τ = (20 kg)(9.8 m/s²)(25 m)

<u>τ = 4900 N.m</u>

<u></u>

c)

Here,

m = 8 kg

r = 62.5 m

Therefore,

τ = (8 kg)(9.8 m/s²)(62.5 m)

<u>τ = 4900 N.m</u>

<u></u>

Hence, the correct answer will be:

<u>e. The torque is the same for all cases.</u>

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