Question

which is the correct equation for calculating the kinetic energy of an object?

$ke = mgh$

$ke = \frac{1}{2}mv^{2}$

$ke = \frac{1}{2}at^{2}$

$ke = \frac{1}{4}g^{2}$

Explanation:

Kinetic energy is the energy of an object in motion. The formula \(KE=\frac{1}{2}mv^{2}\) is derived from work - energy principles. Here, \(m\) is the mass of the object and \(v\) is its velocity.

• \(KE = mgh\) is the formula for gravitational potential energy (\(m\) is mass, \(g\) is acceleration due to gravity, \(h\) is height).
• \(KE=\frac{1}{2}at^{2}\) is not a formula for kinetic energy. \(\frac{1}{2}at^{2}\) is part of the kinematic equation \(s = ut+\frac{1}{2}at^{2}\) (where \(s\) is displacement, \(u\) is initial velocity, \(a\) is acceleration, \(t\) is time).
• \(KE=\frac{1}{4}g^{2}\) is not a valid formula for any physical quantity related to energy.

Answer:

\(KE=\frac{1}{2}mv^{2}\)