question about momentum Watch
impulse is Force x Time
so you can read off the change in momentum from the graph and the time taken and get the force from that (making sure to convert to SI units first)
Now, Newton's second law states that Force is directly proportional to the rate of change of momentum. THe y-axis is momentum and the change is 1 (difference between 0.4 and -0.6).
We divide this by the time taken for the change in momentum to occur which is 2x10^-3 which is equal to 250N.
I think the main bit to remember here is the axis units and also that force = rate of change of momentum.