### Concept Items

## 8.1 Linear Momentum, Force, and Impulse

What is impulse?

- Change in velocity
- Change in momentum
- Rate of change of velocity
- Rate of change of momentum

In which equation of Newton’s second law is mass assumed to be constant?

- $\text{F}=ma$
- $\text{F}=\frac{\text{\Delta}\text{p}}{\text{\Delta}t}$
- $\text{F}=\text{\Delta}\text{p}\text{\Delta}t$
- $\text{F}=\frac{\text{\Delta}m}{\text{\Delta}a}$

What is the equation for linear momentum?

- $\text{p}=m\text{v}$
- $\text{p}=m\text{/}\text{v}$
- $\text{p}=\text{m}{\text{v}}^{2}$
- $\text{p}=\frac{1}{2}\text{m}{\text{v}}^{2}$

## 8.2 Conservation of Momentum

What is angular momentum?

- The sum of moment of inertia and angular velocity
- The ratio of moment of inertia to angular velocity
- The product of moment of inertia and angular velocity
- Half the product of moment of inertia and square of angular velocity

What is an isolated system?

- A system in which the net internal force is zero
- A system in which the net external force is zero
- A system in which the net internal force is a nonzero constant
- A system in which the net external force is a nonzero constant

## 8.3 Elastic and Inelastic Collisions

In the equation **p**_{1} + **p**_{2} = **p**'_{1} + **p**'_{2} for the collision of two objects, what is the assumption made regarding the friction acting on the objects?

- Friction is zero.
- Friction is nearly zero.
- Friction acts constantly.
- Friction before and after the impact remains the same.

What is an inelastic collision?

- when objects stick together after impact, and their internal energy is not conserved
- when objects stick together after impact, and their internal energy is conserved
- when objects stick together after impact, and always come to rest instantaneously after collision
- when objects stick together after impact, and their internal energy increases