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 \(m\). Multiply both sides by \(2\) to get \(2KE = mv^{2}\), then \(m=\frac{2KE}{v^{2}}\).

Step2: Substitute the given values

We know \(KE = 480\space J\) and \(v = 8\space m/s\). Substitute into the formula: \(m=\frac{2\times480}{8^{2}}\).
First, calculate \(2\times480=960\) and \(8^{2}=64\). Then \(m=\frac{960}{64}\).

Step3: Calculate the value of \(m\)

\(\frac{960}{64}=15\).

Answer:

15 kg