Chapter 2 Lesson 2

The force that two surfaces exert on each other when they rub against each other is called

• gravity
• friction
• weight 
• net force

What are two factors that affect the force of friction?

• types of surface and how hard the surfaces are pushed together
• length of surface and how soft the surfaces are pushed together
• type of surface and how fast the surfaces are pushed together
• type of surface and how slow the surfaces are pushed together

Friction _____ when surfaces push harder against each other.

• decreases
• stays the same
• increases
• increases and decreases

_____ surfaces produce less friction than _____ rough surfaces. 

• rough, smooth
• small, large
• smooth, rough
• large, small

_____ friction occurs when two solid surfaces slide over each other and make moving objects slow down and stop?

• rolling friction 
• fluid friction
• sliding friction
• static friction

_____ friction occurs when a solid object moves through a fluid.

• fluid friction
• sliding friction 
• static friction
• rolling friction

_____ friction occurs when an object rolls across a surface.

• static friction
• sliding friction
• fluid friction
• rolling friction

_____ friction acts between objects that are not moving?

• rolling friction
• fluid friction
• sliding friction
• static friction

What type of friction occur between your bike tires and the ground when you ride over cement, ride through a puddle, and apply your brakes?

• rolling, fluid, and sliding
• rolling, fluid, and static
• static, fluid, and sliding
• static, sliding, and rolling

A force that pulls objects towards each other is called 

• friction
• net force
• gravity
•  static friction