Physics, Quiz 4.

A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is

30 m/s.

Which of the following statements includes all the essential elements of Newton's law of inertia (first law)?

A body persists in its state of rest or of uniform motion in a straight line unless acted on by a non-zero net external force.

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron (same material) has twice as much

All of the others.

An inertial reference frame is one of which

Newton's first law describes the behavior of matter.

According to Newton's law of inertia, a rail road train in motion on a flat surface should continue going forever even if its engine is turned off. We never observe this because in real life, railroad trains

always have forces that oppose their motion.

If no external forces are acting on a moving object it will

continue moving at the same velocity.

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor

exactly below the midpoint of the ceiling.

If one object has twice as much mass as another object, it also has twice as much

inertia.

If your automobile runs out of fuel while you are driving the engine stops but you do not come to an abrupt stop. The concept that most explains why is

inertia.

A kilogram is a measure of an object's

inertial mass.

A force is a vector quantity because it has both

magnitude and direction.

When a rocket ship accelerating in outer space (no friction) runs out of fuel it

no longer accelerates.

A moving body must undergo a change in

position.

The last instant just before an airplane crashes a passenger jumps out the door and falls only two feet to the ground. The passenger is

probably hurt or killed.