What is a torque?

What is the torque exerted by the axe on the grindstone?

• A disc-shaped grindstone of mass 3.0 kg and radius 8.0 cm is spinning at 600 rev/min. After the power is shut off, a man continues to sharpen his axe by holding it against the grindstone until it stops 10 s later. What is the torque exerted by the axe on the grindstone? I worked out the problem, and I know the magnitude of the torque is 0.06 N*m. However, my problem is that the direction of the torque exerted by the axe would then be negative? Is it incorrect to state that the torque is positive?

• Answer:

  horse power