Q1PE - College Physics (Urone)

Question

A 63.0 kg sprinter starts a race with an acceleration of 4.20 m/s². What is the net external force on him?

Step-by-Step Solution

Answer

The net external force is 264.6 N.

Step 1: Given Data

The given data is listed as below,

• Mass of the sprinter is, $\mathrm{m}$ = 63 kg.

• Acceleration is,  $\mathrm{a}$ = 4.20 m/s2.

Step 2: Concept of Newton’s second law of motion

Significant Newton’s second law of motion states that the acceleration of a system is directly proportional to the net external force acting on the system and is inversely proportional to the mass of the system. Mathematically,

${\mathrm{F}}_{\mathrm{net}}=\mathrm{ma}$  ………. (i)

Here, 

(a). ${\mathrm{F}}_{\mathrm{net}}$ is the net force

(b).  $\mathrm{m}$ is the mass

(c). $\mathrm{a}$ is the acceleration.

Step 3: Determine the net external force acting on the sprinter

Substitute 63 kg for  $\mathrm{m}$ and 4.20 m/s2 for  $\mathrm{a}$  in equation (i),

$$\begin{gathered} {\mathrm{F}}_{\mathrm{net}}=63 \mathrm{kg}\times 4.20 \mathrm{m}/{\mathrm{s}}^2 \\ =264.6 \mathrm{kg}‐\mathrm{m}/{\mathrm{s}}^2 \\ =264.6 \mathrm{N} \end{gathered}$$

Hence, the net external force on him is 264.6 N.