Ima Speeder and her three friends take her dad’s car out for a joy ride. Encouraged by her
friends, Ima exceeds the speed limit. They are travelling 76 mph when a deer crosses the road in
front of the car. Ima reacts and slams on the brakes, but still hits the deer. Answer the following
questions about Ima’s driving, her dad’s car, and the deer.
1. What is the speed of the car in m/s?
2. The car has a mass of 1280 kg. The average mass of the four occupants is 63 kg. What is the
momentum of the car (and occupants) while travelling at 76 mph? (Answer in kg m/s.)
3. What is the kinetic energy of the car (and occupants) while travelling 76 mph? (in joules.)
4. What is the potential energy of the car at this speed? Explain.
5. Ima’s complex reaction time of 2.25 seconds is a bit slower than expected because she is
distracted by her friends. What distance, in meters, does the car travel before Ima applies the
brakes?
6. The car hits the deer before Ima can fully stop. Her speed is 28 mph when the collision
occurs. What is the speed of the car in m/s when the collision occurs?
7. What is the kinetic energy of the car and occupants at this speed? (in joules.)
8. What is the potential energy of the car at the speed when the collision occurs? Explain.
9. What is the momentum of the car and passengers immediately before the collision occurs?
10. The deer is standing still when it is struck by the car. The deer has a mass of 195 kg, and
sticks to the front of the car. What is the change in velocity for the car (and occupants)
resulting from the collision?
11. What is the impulse experienced by the car during the collision?
12. What is the impulse experienced by the deer during the collision?
13. The duration of contact for the collision is 0.25 seconds. With what force did the car strike
the deer?
14. What is the momentum of the car immediately following the collision?