Question

Usain Bolt has a mass of 94.1 kg and he had a KE of 7,250 J when running the one hundred meter dash. Calculate how fast he was running

Answer 1

`\displaystyle v = 12.4134 \ m/s`

General Formulas and Concepts:

Energy

Kinetic Energy Formula:
`\displaystyle KE = (1)/(2)mv^2`

• m is mass (in kg)
• v is velocity (in m/s)

Step-by-step explanation:

Step 1: Define

Identify variables.

KE = 7250 J

m= 94.1 kg

Step 2: Solve for v

1. Substitute in variables [Kinetic Energy Formula]:
   `\displaystyle 7250 = (1)/(2)(94.1)v^2`
2. Isolate v term:
   `\displaystyle 154.091 = v^2`
3. Isolate v:
   `\displaystyle v = 12.4134`

Topic: AP Physics 1 - Algebra Based

Unit: Energy