Physics

Physics

Problem

An object of mass 4 kg4\,\text{kg} has kinetic energy 50 J50\,\text{J}. What is its speed? a) 3.5 m s−13.5\,\text{m s}^{-1} b) 10 m s−110\,\text{m s}^{-1} c) 5 m s−15\,\text{m s}^{-1} d) 7 m s−17\,\text{m s}^{-1}
Intuitive explanation

Kinetic energy is all about how motion stores energy in mass. The key is to use the formula KE=12mv2KE = \frac{1}{2}mv^2 and rearrange it to isolate speed—you're solving for vv given the energy and mass. Once you rearrange, you'll need to carefully handle the square root to find the actual speed value.

Intuitive explanation

Kinetic energy is all about how motion stores energy in mass. The key is to use the formula KE=12mv2KE = \frac{1}{2}mv^2 and rearrange it to isolate speed—you're solving for vv given the energy and mass. Once you rearrange, you'll need to carefully handle the square root to find the actual speed value.

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