Question

1. a 63.0 - kg sprinter starts a race with an acceleration of 4.20 m/s². what is the net external force on him? 2. if the sprinter from the previous problem

Explanation:

Step1: Identify the formula

We use Newton's second - law $F = ma$, where $F$ is the net force, $m$ is the mass and $a$ is the acceleration.

Step2: Substitute the given values

Given $m = 63.0\ kg$ and $a=4.20\ m/s^{2}$. Substitute into the formula: $F=(63.0\ kg)\times(4.20\ m/s^{2})$.

Step3: Calculate the result

$F = 63.0\times4.20=264.6\ N$. Rounding to three significant digits, $F = 265\ N$.

Answer:

$265\ N$