What force exists in "motionless situations", for example, that keeps a book sitting still on a table and not sliding off by itself.

• static friction

• dynamic friction

• weight

• electrical force

What type of friction means "unmoving" or "unchanging"?

• static friction

• dynamic friction

• gravitational friction

• elastic friction

Which statement is TRUE:

• static friction is always greater than dynamic friction

• dynamic friction is always greater than static friction

• velocity and speed are the same thing

• a free-body diagram contains all objects in a situation

This force occurs when one object rubs against another.

• dynamic friction

• static friction

• gravitational force

• electrical force

This type of friction means "changing".

• dynamic friction

• static friction

• gravitational friction

• elastic friction

Complete this phrase: "It is always easier to keep something moving than to..."

• "...start it moving."

• "...stop it from moving."

• "...make it move faster."

• "...make it move slower."

Tags

NGSS.HS-PS2-1

On a force diagram, friction is usually drawn where...

• two surfaces make contact

• water touches air

• a surface is affected by gravity

• no forces exist

Which of the following is the best way to catch a water balloon to prevent it from breaking?

• slow it down as you catch it

• catch it suddenly

• move your hands towards the balloon to get greater impact

• squeeze the balloon as it hits your hands

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

How does a baseball glove slow down a baseball?

• the padding depresses to create a cushion that slows the ball

• the leather in the glove heats up to absorb energy

• the padding creates a force that pushes back against the ball

• the glove stops gravity

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

NGSS.MS-PS3-5

How does a trapeze net protect an acrobat from breaking their bones?

• the net slows down their fall

• the net cushions their bones

• the net stops them quickly

• the net increases their speed

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-1

NGSS.MS-PS3-5