How much impulse is given to a 25 kg train car that is accelerated from rest to 12 m/s in 4 sec?

25 kg * 12 m/s.

The time doesn't matter when calculating the impulse. Impulse equals momentum change.

To calculate the impulse experienced by the train car, we can use the impulse-momentum principle, which states that the change in momentum of an object is equal to the impulse applied to it.

The formula for impulse is given by:

Impulse = Change in momentum

The formula for momentum is:

Momentum = mass × velocity

Given:
Mass of the train car (m) = 25 kg
Initial velocity (u) = 0 m/s (since it starts from rest)
Final velocity (v) = 12 m/s
Time taken (t) = 4 sec

First, let's calculate the change in momentum using the formula:

Change in momentum = Final momentum - Initial momentum

Final momentum = m × v
Initial momentum = m × u

Substituting the given values:

Final momentum = 25 kg × 12 m/s = 300 kg·m/s
Initial momentum = 25 kg × 0 m/s = 0 kg·m/s

Change in momentum = 300 kg·m/s - 0 kg·m/s = 300 kg·m/s

Therefore, the change in momentum (impulse) experienced by the train car is 300 kg·m/s.