### Problems

#### 8.1 Linear Momentum, Force, and Impulse

- 1\,\text{kg}
- 2\,\text{kg}
- 5\,\text{kg}
- 250\,\text{kg}

For how long should a force of 130 N be applied to an object of mass 50 kg to change its speed from 20 m/s to 60 m/s?

- 0.031 s
- 0.065 s
- 15.4 s
- 40 s

#### 8.3 Elastic and Inelastic Collisions

In an elastic collision, an object with momentum 25 kgâ‹…m/s collides with another that has a momentum 35 kgâ‹…m/s. The first objectâ€™s momentum changes to 15 kgâ‹…m/s. What is the momentum of the second object after the collision?

- 5 kgâ‹…m/s
- 10 kgâ‹…m/s
- 25 kgâ‹…m/s
- 75 kgâ‹…m/s

- -0.12\,\text{m/s}
- 0\,\text{m/s}
- 0.12\,\text{m/s}
- 7.5\,\text{m/s}