Bennett Mechanical Test Bennett Mechanical Friction and Inclined Planes Questions and Answers 1 — Questions and Answers
Question 1: Which type of friction acts on a stationary object that is being pushed but has not yet moved?
- Kinetic friction
- Rolling friction
- Static friction (Correct answer)
- Fluid friction
Correct answer: Static friction
Static friction resists the initiation of motion between surfaces that are not moving relative to each other.
Question 2: A 100 N block slides on a surface with a coefficient of kinetic friction of 0.3. What is the friction force?
- 0.3 N
- 30 N (Correct answer)
- 300 N
- 3 N
Correct answer: 30 N
Friction force = μk × Normal force = 0.3 × 100 = 30 N.
Question 3: What is the mechanical advantage of a frictionless inclined plane that is 10 m long and 2 m high?
- 2
- 5 (Correct answer)
- 8
- 20
Correct answer: 5
Mechanical advantage of an inclined plane = length / height = 10 / 2 = 5.
Question 4: Compared to sliding (kinetic) friction, rolling friction between the same surfaces is generally:
- Greater
- Equal
- Less (Correct answer)
- Unpredictable
Correct answer: Less
Rolling friction is significantly less than sliding friction because contact area and deformation are reduced.
Question 5: On a 30° inclined plane, what is the component of a 200 N weight acting parallel to the slope?
- 100 N (Correct answer)
- 173 N
- 200 N
- 50 N
Correct answer: 100 N
Parallel component = mg sin30° = 200 × 0.5 = 100 N.
Question 6: Adding a lubricant between two moving surfaces primarily reduces which quantity?
- Normal force
- Friction (Correct answer)
- Weight
- Inertia
Correct answer: Friction
Lubricants reduce the coefficient of friction by creating a fluid layer that separates the two surfaces.
Bennett Mechanical Test Bennett Mechanical Friction and Inclined Planes Questions and Answers 1
Which type of friction acts on a stationary object that is being pushed but has not yet moved?