Question

A comet with a mass of 7.85 × 1011 kg is moving with a velocity of 25,000 m/s. calculate its kinetic energy.

Answer 1

The kinetic energy of an object is given by:
$K= \frac{1}{2}mv^2$
where
K is the kinetic energy
m is the mass of the object
v is its velocity.

The comet in our problem has a mass of $m=7.85 \cdot 10^{11} kg$ and a velocity of $v=25000 m/s$, so its kinetic energy is:
$K= \frac{1}{2}(7.85 \cdot 10^{11} kg)(25000 m/s)^2=2.45 \cdot 10^{20}J$