Question

1. Linear Momentum of an object is conserved

1. At all times    b. Only when the net external force on the object is Zero

3. When the net external torque on the object is Zero    d. Never

2. A truck of mass 4000 (kg) is moving at 10 (m/s). A car of mass 1000 (kg) is moving at 40 (m/s).

So, the truck’s momentum, compared to the car, is

1. Greater    b. Smaller    c. the same      d. Cannot say without knowing their accelerations

3. A 1000 (kg) car is travelling at 60 (mph) when it collides with a 4000 (kg) truck travelling at 50 (mph) in the same direction. The time of impact between the two vehicles is 50 (ms). Ignoring friction, what is the velocity of the two vehicles after collision if they are stuck?

1. 52 (m/s)       b. 52 (mph)     c. 24 (m/s)      d. 24 (mph)      e. 0

4. In the above, what is the force of collision on the car from the truck?

1. 1,440,000 (N)    b. 400,000 (N)     c. 320,000 (N)       d. 0

5. In question (4), the force of collision on the truck from the car is

1. Greater        b. Smaller       c. The same as      d. Zero

than the force of collision on the car from the truck

6. Angular Momentum of an object is

1. Mass of the object times its velocity
2. Mass of the object times its angular velocity
3. Rotational Inertia of the object times its angular velocity
4. Rotational Inertia of the object times the Angle of rotation

7. A figure skater goes around the ice rink in a circular path with her arms and legs extended out from the axis of rotation. When she pulls her arms and legs towards her body, her angular velocity

1. Increases        b. Decreases        c. Stays the same       d. Cannot say without knowing her mass

8. When work is done on an object, it can be converted to energy. Under ideal conditions, the work done is

1. Greater than the energy        b. Equal to the energy
2. Smaller than the energy        d. Greater or smaller than the energy depending on Mass

9. The above is a result of the

1. Conservation of Mass          b. Conservation of Momentum
2. Conservation of Energy       d. All of the above

Answer 1