19,879
edits
Changes
→Example Calculations
===Example Calculations===
{| class="wikitable"
| style="height:20px; width:200px300px; text-align:center;" |A car travelling at 20m/s collides with a lamppost and comes to a complete stop in 0.16 seconds. If the passenger has a [[mass]] of 80kg, calculate the [[force]] exerted by the seat belt on the passenger correct to two [[Significant Figures|significant figures]].| style="height:20px; width:200px300px; text-align:center;" |During a crash the air bag activates. By the time the car stops the drivers 5kg head is still moving forward with a velocity of 2.4m/s and collides with the airbag. This collision lasts for 0.25 seconds. Calculate the [[force]] between the air bag and the person's head during the collision.
|-
| style="height:20px; width:200px300px; text-align:left;" |'''1. State the known quantities'''
Δv = 20m/s
m = 80kg
| style="height:20px; width:200px300px; text-align:left;" |'''1. State the known quantities'''
Δv = 2.4m/s
m = 5kg
|-
| style="height:20px; width:200px300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>F = \frac{m \Delta v}{t}</math>
<math>F = 10000N</math>
| style="height:20px; width:200px300px; text-align:left;" |'''2. [[Substitute (Maths)|Substitute]] the numbers into the [[equation]] and [[Solve (Maths)|solve]].'''
<math>F = \frac{m \Delta v}{t}</math>