Question

1. a 4 kg object has a kinetic energy of 50 j. what is its velocity?

givens:
unknowns:
what are you solving for?
equation to use:
substitute & solve:

Explanation:

Step1: List given values

Mass $m = 4\ \text{kg}$, Kinetic Energy $KE = 50\ \text{J}$
Unknown: Velocity $v$

Step2: Recall kinetic energy formula

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

Step3: Rearrange for velocity

$$v = \sqrt{\frac{2KE}{m}}$$

Step4: Substitute values and calculate

$$v = \sqrt{\frac{2\times50}{4}} = \sqrt{\frac{100}{4}} = \sqrt{25}$$

Answer:

$v = 5\ \text{m/s}$