Question

The torque of a motor is tested using the arrangement shown in the figure below. This is known as a "prony brake". In this set up, a pair of friction platens is tightened together against the motor shaft, and when the motor rotates in the direction shown, a force is exerted on the scale at point P, via a rod of length L. For a motor speed S, in revolutions per minute, and a scale reading of W, in Newtons, what is the power produced by the motor?

Answer 1

The torque exerted by the motor is WL. Power is equal to the torque multiplied by the angular rotation speed of the motor, in radians/second. Therefore, power = WLSπ/30.

Answer 2

The torque is equal to r×F = (3,2,0)×(4,5,0) = (0,0,7) (using cross-product multiplication), and since it's a positive number, the torque acts counterclockwise on the rigid body. The magnitude of r is denoted as |r| = (32+22)1/2 = 131/2, and the magnitude of F is denoted as |F| = (42+52)1/2 = 411/2. The magnitude of the torque is equal to 7, and by definition this is equal to |r||F|sinθ. Solve for θ = 17.65°. 


plz mark me as brainliest dear superstar