Choose the false statement:

Question

Choose the false statement: (A) Kinetic energy may be zero, positive or negative (B) Power, energy and work are all scalars (C) Potential energy zero positive or negative (D) Ballistic pendulum is device for measuring the speed of bullets

Tardigrade Admin · Accepted Answer

If an object of mass m moving with velocity

v \to

, its kinetic energy K is given by

K = \frac{1}{2} m v \to . v \to = \frac{1}{2} m v^{2}

As mass m and

v^{2} (v \to . v \to)

are always positive, therefore kinetic energy is always positive. The kinetic energy can never by negative.

Q. Choose the false statement:

Kinetic energy may be zero, positive or negative

Power, energy and work are all scalars

Potential energy zero positive or negative

Ballistic pendulum is device for measuring the speed of bullets

If an object of mass m moving with velocity v→ , its kinetic energy K is given by K=21​mv→.v→=21​mv2 As mass m and v2(v→.v→) are always positive, therefore kinetic energy is always positive. The kinetic energy can never by negative.

If an object of mass m moving with velocity $v \to$ , its kinetic energy K is given by
$K = \frac{1}{2} m v \to . v \to = \frac{1}{2} m v^{2}$
As mass m and $v^{2} (v \to . v \to)$ are always positive, therefore kinetic energy is always positive. The kinetic energy can never by negative.