Static and kinetic friction
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Ari pulls a 5 kg box at a constant velocity across a floor with a horizontal pull of 9.8 N. With g = 9.8 m/s², what is μk?
Bo pulls a 6 kg box at a constant velocity across a floor with a horizontal pull of 14.7 N. With g = 9.8 m/s², what is μk?
Esme pulls a 4 kg box at a constant velocity across a floor with a horizontal pull of 11.76 N. With g = 9.8 m/s², what is μk?
In the friction graph, what is μk for the block on the board, Jun?
- 3.33
- 3
- 12
- 0.3
Using the friction graph, what friction would a 50 N normal force give, Kira?
Use the picture in question 4.
- 12 N
- 167 N
- 50 N
- 15 N
What does the straight line in the friction graph show, Luz?
Use the picture in question 4.
- Friction equals the normal force
- Friction is proportional to the normal force
- Friction falls as the normal force grows
- Friction doesn't depend on the normal force
Milo says a box at rest on a level floor always feels its full μs N of static friction. Agree or disagree?
- Agree: μ is the normal force ÷ friction
- Disagree: it only matches the push
- Agree: static friction sits at its limit
- Agree: and kinetic friction is even bigger
Noah says it takes more force to keep a box sliding than to get it started. Agree or disagree?
- Agree: friction at rest sits at its limit
- Disagree: static friction is usually larger
- Agree: μ is N ÷ f
- Agree: kinetic friction is usually larger
Pia says μ = friction ÷ normal force, so 6 N of friction with a 20 N normal force means μ = 0.3. Agree or disagree?
- Disagree: μ = 20 ÷ 6
- Disagree: kinetic friction beats static
- Disagree: static friction stays at its limit
- Agree: 6 ÷ 20 = 0.3
Why do sleds use thin steel runners on snow and ice, Zee?
- Runners make the sled heavier
- Runners remove the normal force
- Steel on ice has a very small μ
- Steel has a very large μ