Question

an object has a velocity of 8 m/s and a kinetic energy of 480 j. what is the mass of the object? (formula: $ke=\frac{1}{2}mv^{2}$) 7.5 kg 15 kg 60 kg 120 kg

Explanation:

Step1: Rearrange the kinetic - energy formula for mass.

Given $KE=\frac{1}{2}mv^{2}$, we can solve for $m$. First, multiply both sides of the equation by $2$ to get $2KE = mv^{2}$. Then, divide both sides by $v^{2}$ to obtain $m=\frac{2KE}{v^{2}}$.

Step2: Substitute the given values.

We know that $KE = 480\ J$ and $v = 8\ m/s$. Substitute these values into the formula $m=\frac{2KE}{v^{2}}$, so $m=\frac{2\times480}{8^{2}}$.

Step3: Calculate the mass.

First, calculate $8^{2}=64$ and $2\times480 = 960$. Then, $m=\frac{960}{64}=15\ kg$.

Answer:

15 kg