The first five questions of this practice quiz are open to everybody, with no code and no sign-in. AP Physics C Mechanics, Unit 2, force and translational dynamics.
1. A thin rod of length \(L\) lies along the \(x\)-axis from 0 to \(L\) with linear mass density \(\lambda(x)=\lambda_0\dfrac{x}{L}\). Its center of mass is at
- \(x=L/2\)
- \(x=L/3\)
- \(x=2L/3\)
- \(x=3L/4\)
2. Two skaters stand at rest on frictionless ice and push each other apart. While they are moving apart, the center of mass of the pair
- stays exactly where it was
- moves toward the heavier skater
- moves toward the lighter skater
- moves in the direction of the larger push
3. A uniform rope of mass \(m\) hangs from a ceiling with nothing attached to its lower end. The tension in the rope is
- the same everywhere along it
- greatest at the top and zero at the bottom
- greatest at the bottom and zero at the top
- zero everywhere, since nothing hangs on it
4. A truck collides with a small car. During the collision the magnitude of the force the truck exerts on the car, compared with the force the car exerts on the truck, is
- larger, because the truck is heavier
- larger, because the truck was moving faster
- the same
- smaller, because the car is easier to accelerate
5. An object moves in a straight line at constant speed. Which statement must be true?
- No forces are exerted on it
- The net force exerted on it is zero
- Exactly one force is exerted on it
- The forces on it are all vertical