Module 2
the law of inertia applies to
both stationary and moving objects
According to Newton's law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains
Always have forces that oppose their motion
If you slide a hockey puck across a frictionless patch of ice, there must be a horizontal force on it to keep it in motion. (T/F)
False
An object following a straight-line path at constant speed
Has zero acceleration
A moving body must undergo a change in
Position
A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that
The milk carton has inertia
Inertia is the property that every material object has that causes the object to resist changes in its state of motion. Mass is a measure of inertia (T/F)
True
The reason a penny thrown straight up inside a bus will come back to your hand is that you, the bus, the air inside the bus, and the penny are all moving at the same velocity.
True
If no external forces are acting on a moving object, it will
continue moving at the same velocity
A truck is moving at a 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 a hockey puck slides on a perfectly frictionless surface, it will eventually slow down because of its inertia
false
Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to
follow a straight-line path
an object following a straight-line path at constant speed:
has zero acceleration
which of the following terms represents an object's resistance to change motion?
inertia or mass
the amount of matter in an object is called its
mass
the units of force can be in
pounds or newtons
As an object freely falls downward, its
velocity increases
If you were an astronaut in space and you threw a wrench, the amount of force needed to keep it going would be:
zero