Question

1. if a cars kinetic energy is 100,000 j at 10 m/s, what will it be at 20 m/s? 50,000 j 200,000 j 800,000 j 400,000 j

Explanation:

Step1: Recall the kinetic energy formula

The formula for kinetic energy is \(KE=\frac{1}{2}mv^{2}\). When \(KE = 100000\space J\) and \(v = 10\space m/s\), we can find the mass \(m\). From \(KE=\frac{1}{2}mv^{2}\), we get \(m=\frac{2KE}{v^{2}}\). Substituting the values: \(m=\frac{2\times100000}{10^{2}}=\frac{200000}{100}=2000\space kg\).

Step2: Calculate the new kinetic energy

Now, with \(m = 2000\space kg\) and \(v = 20\space m/s\), use the kinetic energy formula \(KE=\frac{1}{2}mv^{2}\). Substitute \(m = 2000\) and \(v = 20\): \(KE=\frac{1}{2}\times2000\times20^{2}\). First, calculate \(20^{2}=400\). Then \(\frac{1}{2}\times2000\times400=( \frac{1}{2}\times2000)\times400 = 1000\times400=400000\space J\).

Answer:

\(400000\space J\)