Question

Power is defined as the rate of doing work. A cyclist is moving along a flat road. He has a mass of 70 kg and is pedaling to maintain a constant speed of 5 m/s. The cyclist experiences a frictional force of 20 N acting opposite to the direction of motion.

Assertion: A person working on a horizontal road with a load on his head does no work. Reason: No work is said to be done, if directions of force and displacement of load are perpendicular to each other.

(a) Define work done. How can we calculate work done by (i) Constant force (ii) Variable force and (iii) From graph if an object is displaced along a straight line. (b) Find work done by a force F = 2x (SI unit) if it displaces an object from origin to a Point (1, 2,-2)

The diagram shows a wheel with a handle. Two forces, F1 and F2 of equal magnitudes are acting on the handle as shown in the diagram.