What term or phrase best describes a point that appears to stay in place and can be used to detect the motion of an object?

• reference point
• a ruler
• a compass
• a beacon

What is an object's change in position relative to a reference point called?

• velocity
• motion
• average speed
• acceleration

What two factors are needed to determine speed?

• distance and time
• distance and velocity
• direction and time
• velocity and friction

A combined force that does not cause movement is __________________.

• balanced
• unbalanced
• kinetic friction
• newtons

The combination of all forces acting on an object is 

• net force
• average speed
• balanced
• unbalanced

A substance that can be put on the surface to reduce friction is known as a 

• lubricant
• force 

The rate at which velocity changes over time is called _________________.

• speed
• distance
• acceleration
• time

A decrease in speed is sometimes called __________________.

• deceleration
• centripetal acceleration
• positive acceleration
• negative velocity

 Two factors that can affect the magnitude of friction between two surfaces are strength of the force and _____________________

• surface material
• speed
• none of the above
• direction

How do calculate average speed?

• t/d
• d/t
• a/t
• v/t