Which of the following statements is incorrect?

Options

A. Kinetic energy may be zero, positive or negative
B. Power, energy and work are all scalars
C. Potential energy may be zero, positive or negative
D. Ballistic pendulum is a device for measuring the speed of bullets

Answer

A

Explanation

If an object of mass m moving with velocity `vecv`, its kinetic energy K is given by
`K=1/2 mvecv.vecv=1/2 mv^2`
As mass m and `v^2(vecv.vecv)` always positive, therefore kinetic energy is always positive. The kinetic energy can never be negative.