A man with a box on his head is climbing up a ladder. The work done by the man on the box is

(a) Positive

(b) Negative

(c) Zero

(d) Undefined.

When the speed of a ball is doubled its kinetic energy

(a) Remains same

(b) gets doubled

(c) Becomes half

(d) becomes 4 times

Two bodies of unequal masses are dropped from the top of building. Which of the following is equal for both bodies at any instance?

(a) Speed

(b) force of gravity

(c) potential energy

(d) kinetic energy

A porter with a suitcase on his head is climbing up steps with uniform speed. The work done by the “weight of the suitcase” on the suitcase is

(a) Positive

(b) Negative

(c) Zero

(d) Undefined

How will the increasing energy needs and conservation of energy influence international peace, cooperation and security? Discuss.