### Extended Response

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

- No, because momentum is independent of the velocity of the object.
- No, because momentum is independent of the mass of the object.
- Yes, if the lighter objectâ€™s velocity is considerably high.
- Yes, if the lighter objectâ€™s velocity is considerably low.

- The softer surface increases the duration of the impact, thereby reducing the effect of the force.
- The softer surface decreases the duration of the impact, thereby reducing the effect of the force.
- The softer surface increases the duration of the impact, thereby increasing the effect of the force.
- The softer surface decreases the duration of the impact, thereby increasing the effect of the force.

Can we use the equation ${\text{F}}_{\text{net}}=\frac{\text{\xce\u201d}p}{\text{\xce\u201d}t}$ when the mass is constant?

- No, because the given equation is applicable for the variable mass only.
- No, because the given equation is not applicable for the constant mass.
- Yes, and the resultant equation is F =
*m***v** - Yes, and the resultant equation is F =
*ma*

#### 8.2 Conservation of Momentum

Why does a figure skater spin faster if he pulls his arms and legs in?

- Due to an increase in moment of inertia
- Due to an increase in angular momentum
- Due to conservation of linear momentum
- Due to conservation of angular momentum

#### 8.3 Elastic and Inelastic Collisions

- He should speed up.
- He should slow down.
- He should speed up and then slow down just before the collision.
- He should slow down and then speed up just before the collision.

What approach would you use to solve problems involving 2D collisions?

- Break the momenta into components and then choose a coordinate system.
- Choose a coordinate system and then break the momenta into components.
- Find the total momenta in the x and y directions, and then equate them to solve for the unknown.
- Find the sum of the momenta in the x and y directions, and then equate it to zero to solve for the unknown.