Question

A 75-kg crash test dummy in a car traveling at 30 m/s slams into a brick wall. If the time elapsed during the crash was 0.03 seconds without a seatbelt and 0.3 seconds with a seatbelt, calculate the difference in force. Show all steps in your calculations

Answer 1

Answer:

The difference in force = 67500N

Explanation:

The mass, m = 75 kg

The change in velocity, △v = 30 m/s

The force is calculated using the formula:

$F=\frac{m(\Delta v)}{\Delta t}$

For the crash test without a seatbelt:

Time elapsed, △t = 0.03 seconds

Substitute m = 75, △v = 30, and △t = 0.03 into the formula above

$\begin{gathered} F=75(\frac{30}{0.03}) \\ F=75(1000) \\ F=75000N \end{gathered}$

For the crash test with a seatbelt:

Time elapsed, △t = 0.3 seconds

Substitute m = 75, △v = 30, and △t = 0.3 into the formula given

$\begin{gathered} F=75(\frac{30}{0.3}) \\ F=75(100) \\ F=7500N \end{gathered}$

The difference in force = 75000 - 7500

The difference in force = 67500N