Bennett Mechanical Test Force and Torque 3 — Questions and Answers
Question 1: A door is hardest to open when you push:
- Near the hinges (Correct answer)
- At the outer edge
- At the middle
- On the handle
Correct answer: Near the hinges
Pushing near the hinges gives a tiny lever arm, requiring far more force to produce the same torque.
Question 2: Two equal and opposite forces acting on a wheel at its edges create a:
- Couple producing rotation (Correct answer)
- Net forward push
- Zero torque
- Linear acceleration only
Correct answer: Couple producing rotation
A couple is two equal opposite forces that produce pure rotation without net linear force.
Question 3: A 100 N force pushes a crate but it does not move. The opposing force from friction must be:
- 100 N (Correct answer)
- 0 N
- 200 N
- 50 N
Correct answer: 100 N
Since the crate stays still, friction exactly balances the applied force at 100 N.
Question 4: Increasing the force on a wrench while keeping the handle length fixed will:
- Increase the torque (Correct answer)
- Decrease the torque
- Keep torque unchanged
- Reverse the torque direction
Correct answer: Increase the torque
Torque grows directly with applied force when the lever arm stays constant.
Question 5: A nut needs 24 N·m of torque to turn. Using a 0.3 m wrench, what minimum force is needed?
- 80 N (Correct answer)
- 24 N
- 7.2 N
- 240 N
Correct answer: 80 N
Force equals torque divided by length, so 24 ÷ 0.3 = 80 N.
Question 6: Which action does NOT change an object's torque about a pivot?
- Moving the force closer to or farther from the pivot
- Changing the size of the force
- Changing the angle of the force
- Painting the object a different color (Correct answer)
Correct answer: Painting the object a different color
Color has no effect on torque, which depends only on force, distance, and angle.
Question 7: A beam balances on a pivot with equal weights at equal distances. This beam is in:
- Equilibrium (Correct answer)
- Acceleration
- Free fall
- Rotation
Correct answer: Equilibrium
When opposing torques are equal, the beam is balanced and in equilibrium.
Bennett Mechanical Test Force and Torque 3
A door is hardest to open when you push: