A toy car crashes into a wall and rebounds at right angles to the wall, as shown in the plan view.
The graph shows the variation with time of the force acting on the car due to the wall during the collision.
On the axes, draw a graph to show how the momentum of the car varies during the impact. You are not required to give values on the y-axis.
The above is the question. An answer of the question is the below. (either left one or the right one)
I don't understand why it has constant negative or positive gradient. I don't understand why the acceleration (gradient) increases and then decreases again.
Best Answer
Assuming right side to be positive, you could say that when the force on the car(on the left side) is increasing at the time of the collision, the force is causing the car to deaccelerate but as the force is not constant, acceleration is also not constant. So, momentum does not change linearly.
When the force is maximum, the velocity is zero and the acceleration is maximum. After that, the car accelerates in negative $x$ - direction and the velocity first increases rapidly as the force acts in the negative direction. But then as the magnitude of force decreases, acceleration also decreases.