Question

Recently, several cars in the local neighborhood Winding Hills have lost control and fallen from the road into a lake below. The homeowner’s association has asked for your advice regarding a plan to install a barrier at the site of the frequent accidents to keep cars from falling into the lake. The barrier company has provided the HOA with a variety of potential materials to make the barrier from. One member of the HOA, Sal, has recommended selecting the cheapest barrier material because he remembers from his physics class long ago that impulse is equal to change in momentum, so the type of barrier will not affect the force the driver feels. Use the equipment provided to conduct experiments with various bumpers to defend or refute Sal’s claim. Answer the following questions to design your experiment and analysis.

A. What are Sal’s claims? B. Why do airbags reduce injury in car collisions? C. What should stay the same in your experiment as you explore different barriers?

D.What parts, if any, of Sal’s arguments were supported or refuted?

Answer 1

part A:

Sal’s claims are:

1. impulse is change in momentum.

2. the equipment in the barrier wont affect the force faced by the driver when it comes to rest.

part B:

airbags provide a cushioning impact which increases the interaction time with the person and in turn

reduces the amount of force exerted on the person.

thus it reduces injury in car collisions.

part C:

the below parameters should remain constant.

1. initial speed

2. stopping distance

3. make and type of the tyre

part D:

Sal’s argument that impulse is change in momentum is correct.

but his argument that the type of barrier does not affect the force the driver feels is not correct.

depending upon the elasticity of the barrier, it will increase or decrease the contact time

and for the same impulse applied, force applied on the person will decrease or increase.

hence different type of barriers will provide different levels of safety to the driver.