Barron's 2nd Edition PT1 Q39

Barron's Book

39) This question asks us to find the magnitude of the force applied for 5 seconds required to change the speed of the car by 10 m/s.

The simplest way to solve this problem is to use momentum. Since we are concerned with the change in velocity, we will take a look at the impulse(the change in momentum) of the car.

Where J is impulse, p is momentum, m is mass, v is velocity, F is force

The problem gives us the mass, the change in velocity, and the time the force is applied, so we can plug in values to solve for the force.

Where v is velocity, m is mass, t is time, J is impulse, p is momentum, and F is force

Answer: D