Question

4.3 newtons second law of motion: concept of a system you may assume data taken from illustrations is accurate to three digits. 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?

Explanation:

Step1: Recall Newton's Second Law

Newton's second law states that the net force \( F_{net} \) acting on an object is equal to the mass \( m \) of the object multiplied by its acceleration \( a \), i.e., \( F_{net} = m \cdot a \).

Step2: Identify given values

The mass \( m \) of the sprinter is \( 63.0 \, \text{kg} \) and the acceleration \( a \) is \( 4.20 \, \text{m/s}^2 \).

Step3: Substitute values into the formula

Substitute \( m = 63.0 \, \text{kg} \) and \( a = 4.20 \, \text{m/s}^2 \) into \( F_{net} = m \cdot a \):
\[
F_{net} = 63.0 \, \text{kg} \times 4.20 \, \text{m/s}^2
\]

Step4: Calculate the result

\[
63.0 \times 4.20 = 264.6
\]
So, the net external force \( F_{net} = 264.6 \, \text{N} \) (since the unit of force is Newton, \( \text{N} \), and \( 1 \, \text{N} = 1 \, \text{kg} \cdot \text{m/s}^2 \)).

Answer:

The net external force on the sprinter is \( \boldsymbol{264.6 \, \text{N}} \).