Answers to Physics Module Questions - Module #6

1. A 7-year old child and a 21-year old college student pull as hard as they can on opposite ends of a rope in a tug-of war. The force is applied to the rope by the child is ___ compared to the force applied by the college student.
1. smaller
2. the same
3. larger
4. depends on how strong the child is
5. none of the above

2. A railroad car that is initially at rest is hit by an identical railroad car traveling with a momentum of 100 units. The cars stick together and move down the railroad tracks. The combined momentum of the cars after the collision is
1. 200 units
2. 100 units
3. 50 units
4. 0 units
5. none of the above

3. An athlete performs a high jump. As she lands, she bends her knees as she reaches the ground. This increases the time of impact. The result is to ___ the force that her body experiences.
1. increase
2. keep the same
3. reduce
4. the answer depends on how high she jumped
5. none of the above

4. A canon ball travelling at 10 m/s has a momentum of 50 kg m/s. What is the mass of the ball?
1. 10 kg
2. 50 kg
3. 20 kg
4. 5 kg
5. 25 kg
6. none of the above

5. A car travelling at 10 km/hr runs into a haystack and comes to a stop. This is less dangerous than if the car had driven into a concrete wall. This is because driving into the haystack results in
1. reduced impulse
2. increased impulse
3. the same impulse
4. reduced change in momentum
5. increased change in momentum
6. the same change in momentum
7. increased time of impact and reduced impact force
8. increased time of impact and increased impact force
9. reduced time of impact and reduced impact force
10. reduced time of impact and increased impact force