Answer:
The force is applicable according to the newton's third law of motion but the force on the engine is compensated in the form of stess on the fixed parts and rigid links whereas the wheel is free to roll.
Explanation:
This interpretation that the engine applies a force on the train and the train also applies an equal force on the engine and hence the train should not move is wrong because the engine imparts a rotational force in the form of torque on the train and the train imparts an equal force on the engine in the opposite direction but the engine is fixed like a structure on the chassis of the train and consists of rigid links which resist the motion and deformation as compared to the relative motion between the wheels and the rail tracks.
The answer for the following problem is explained below.
<u>Therefore the change in the momentum is 240 kg m/s</u>
Explanation:
Given:
net force() = 120 N
time (t) = 2 seconds
To solve:
change in momentum(Δp)
We know;
= Δp÷t
Δp = × t
Δp = 120 × 2
Δp =240 kg m/s
<u>Therefore the change in the momentum is 240 kg m/s</u>
Choice-D is the correct one.
For the solution, see my detailed response
to the other posting of the same question.
1) Star from the definition of power:
P = work/ time = W / Δt
We know that work is given by force times displacement:
W = F · Δd
Substituting in our formula:
P = F · Δd / <span>Δt
But we know by definition that </span>Δd / <span>Δt = velocity, therefore we can write:
</span>P = F · v
which is the alternative formula saying that Power is equal to Force times Velocity
2) No, it is not a violation of the Law of conservation of energy because as the spring slows down, the kinetic energy is transformed into potential energy and their sum stays constant.