Forces, Friction, and Gravity

A napkin stays on your lap on a breezy summer day because of _______.

• Kinetic friction
• Static friction
• Rolling friction

A feather and a rock dropped at the same time from the same height would land at the same time when dropped _____________.

• By an astronaut on the moon
• By you in your front yard
• By Galileo in Italy

When an object receives unbalanced forces, the object may...

• change direction
• change speed
• starts to move
• All are correct 

A skydiver experiences two forces acting upon him once outside the plane.  They are… 

• Gravitational pull and fluid friction
• Static friction and free fall
• Acceleration and sliding friction

Forces occur in pairs and are…

• Balanced if equal and opposite in direction
• Unbalanced if not equal in size and opposite in direction
• Measured in Newtons
• All of the above

A force is a push or ______. 

• Pull
• Newtons
• Gravity

A ball is dropped from a rooftop.  What is the ball’s velocity after 3 seconds of fall? Use the formula… (Δv=g⋅t) (Assume there is NO air resistance)

• 6.81 m/s
• 29.43 m/s
• 3.27 m/s

Force is measured in ________. 

• Newtons 
• Mass
• Pounds

Galileo proved that the rate at which an object falls __________. 

• Is “not” affected by the objects mass 
• Decreases with a decrease in mass
• Increases with an increase in mass

When a falling object stops accelerating and falls at a constant rate, this is called______. 

• Free fall
• Terminal velocity 
• Bungee jumping