Question

A missile is launched with a velocity less than the escape velocity from earth. The sum of its kinetic energy and potential energy is

• A. positive
• B. negative
• C. zero
• D. may be positive or negative depending on the direction of projection

Answer 1

The correct option is B negative

The potential at infinite distance from earth is taken to be zero. Thus if it is given energy to give it just the escape velocity, it has no velocity and hence no kinetic energy after reaching infinity and hence zero total energy.

Thus if the given velocity is less than escape velocity of earth, the total energy is negative.