Mountain roads rarely go straight up but wind up gradually. Why?

What is the work done by the tension in the string of a simple pendulum?

State whether the following statement is true or false:
In order to get minimum work,the angle between force and displacement should be $90^{\circ}$.

$(a)$ Define average power. Calculate the total energy consumed in the month of November in a household in which four devices of power $500\, W$ each are used daily for $10\, hours.$
$(b)$ $A$ freely falling object eventually stops on reaching the ground. What happens to its energy?

State whether the following statement is true or false:
When a body falls on the ground and stops,the principle of conservation of energy is violated.

When a coil spring is compressed,the work is done on the spring. The elastic potential energy: