Friction and Universal Law of Gravity

How does friction affect speed?

• more friction decreases speed
• more friction increases speed
• less friction decreases speed

What are 2 factors that determine the amount of friction between 2 objects?

• Force and roughness between surfaces
• hills and valleys and how smooth or rough the surface is
• Amount of force and amount of surface the comes in contact
• The force and the weight exerted on the surfaces

Without friction, an object in motion would never stop.

• true

• false

Rough surfaces have _________ compared to smoother surfaces.

• greater friction

• less friction

• the same level of friction

On which surface will a toy car travel the furthest?

• Carpet
• Polished Wood
• Ice

Tags

NGSS.MS-PS3-5

How can friction be reduced?

• reduce the force acting between the 2 surfaces
• reduce the roughness of the 2 surfaces coming in contact
• use wax, grease or oil
• all of the above are ways of reducing friction

Why do we apply oil on door hinges?

• To increase friction

• To decrease friction

• None of these

Smooth surface has..

• More friction

• Less friction

• None of these

Friction is a...

• non-contact force

• contact force

• magnetic force

• electrostatic force

Answer explanation

Friction happens when two surfaces touch each other, so it is a contact force.

True or False: objects that are smooth have LESS friction than objects that are rough

• TRUE

• FALSE