Question

Calculate the torque (magnitude and direction) about point OOO due to the force F in each of the situations sketched in the figure below (Figure 1). In each case, the force Fand the rod both lie in the plane of the page, the rod has length 6.00 m, and the force has magnitude 5.00 N. Let counterclockwise torques be positive.

Figure < 1 of 1 > 0 900 120.0 (b) 60.00 30.0 2.00 m 60.00 0 o (1)

Answer 1

Length of the rod, l = 6 m

Force, F = 5 N

Torque, Ꞇ = l X F = lF Sinθ

The direction of torque is obtained by finding the direction of cross product of l and F

Part A:

Torque, Ꞇ = lF Sinθ = 6 x 5 x Sin 90 = 30.0 Nm

Torque, Ꞇ = 30.0 Nm and it acts counter clockwise.

Part B:

Torque, Ꞇ = lF Sinθ = 6 x 5 x Sin 120 = 26.0 Nm

Torque, Ꞇ = 26.0 Nm and it acts counter clockwise.

Part C:

Torque, Ꞇ = lF Sinθ = 6 x 5 x Sin 30 = 15.0 Nm

Torque, Ꞇ = 15.0 Nm and it acts counter clockwise.

Part D:

Torque, Ꞇ = lF Sinθ = (6 – 2) x 5 x Sin 60 = 17.3 Nm

Torque, Ꞇ = 17.3 Nm and it acts clockwise

Part E:

Torque, Ꞇ = lF Sinθ = 0x 5 x Sin 0 = 0 Nm

Torque, Ꞇ = 0 Nm

Part F:

Torque, Ꞇ = lF Sinθ = 6 x 5 x Sin 0 = 0 Nm

Torque, Ꞇ = 0 Nm