Torque: Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30° to the plane of the door. Which force exerts the greater torque about the door hinge?

a. the second force (applied at an angle)

b. the first force (applied perpendicular to the door)

c. Both forces exert equal non-zero torques.

d. Both forces exert zero torque.

Question

Van Castillo

Physics

8 November, 18:10

Torque: Two equal-magnitude forces are applied to a door at the doorknob. The first force is applied perpendicular to the door, and the second force is applied at 30° to the plane of the door. Which force exerts the greater torque about the door hinge?

a. the second force (applied at an angle)

b. the first force (applied perpendicular to the door)

c. Both forces exert equal non-zero torques.

d. Both forces exert zero torque.

+2

Answers (1)

Know the Answer?

Smirk · Answer 1

b. the first force (applied perpendicular to the door)

Explanation:

The magnitude of the torque due to force F applied at distance r applied at θ° to the plane of the door.

τ = F*rsinθ

torque due to F1 = F*r sin90 = Fr

torque due to F2 = F*r sin30 = Fr/2

hence greater torque is applied due to first force F1

⇒ option b is correct