An object cannot remain at rest unless which of the following holds?
a. the net force acting on it is zero.
b. the net force acting on it is constant and nonzero.
c. there are no forces at all acting on it.
d. there is only one force acting on it.

Shelly experiences a backward jolt when the driver starts the school bus. which of the following explains this phenomenon? a. the inertia of shelly b. the inertia of the bus c. the normal force of the seats on shelly d. the net force acting on shelly in a backward direction e. a zero net force acting on shelly

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational

You are driving directly behind a pickup truck, going at the same speed as the truck. a crate falls from the bed of the truck to the road. (a) will your car hit the crate before the crate hits the road if you neither brake nor swerve? (b) during the fall, is the horizontal speed of the crate more than, less than, or the same as that of the truck?