Friction... Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force
Means it will keep going until acted on by an outside force, in this case friction
C liquid at room temperature
What are you talking about
Impulse = Force * times and also Impulse = change in momentum.
Given that the mass does not change, change if momentum = mass * (final velocity - initial velocity)
Given that you know mass and initial velocity (which is the velicity before the cart hits the wall) you need the final velocity (which is the velocity after the cart hits the wall).
Answer: the velocity of the cart after it hits the wall.
