Calculating Deceleration and Force of Impact: Skateboarding Physics Homework

[amandamanda3]

Homework Statement

Leroy, who has a mass of 100kg, is skateboarding at 9.0 m/s when he smacks into a brick wall and comes to a dead stop in .2s

a. Show that his deceleration is 45 m/s^2.
b. Show that the force of impact is 4500N.

Homework Equations

I think the only equations that are needed are these:
a= NetForce/m
Weight = mg
Force= ma

The Attempt at a Solution

I tried a number of things, but I couldn't figure out how to get the deceleration. It's not in my book anywhere. All I have are the equations for acceleration. I've tried various configurations, but nothing seems to make sense.

 

[ApexOfDE]

You can not use only 1 eq to find 2 variables. The 2nd eq you need is:
v(t) = v0 + at

Because he stops after 0.2s => v(0.2s) = 0. Plug them and find a => F

 

[kerimek]

Dear Leroy,

I am a scientist and I would like to help you with your skateboarding physics homework. First, let's define some terms. Deceleration is the rate at which an object slows down, and it is measured in meters per second squared (m/s^2). Force is a measure of the interaction between two objects and it is measured in Newtons (N).

To calculate the deceleration of Leroy, we can use the equation a= Δv/Δt, where Δv is the change in velocity and Δt is the change in time. In this case, Leroy is traveling at 9.0 m/s and comes to a stop in 0.2 seconds. This means that his change in velocity is 9.0 m/s and his change in time is 0.2 seconds. Plugging these values into the equation, we get:

a= (9.0 m/s)/(0.2 s) = 45 m/s^2

Therefore, Leroy's deceleration is 45 m/s^2.

To calculate the force of impact, we can use the equation F=ma, where F is the force, m is the mass, and a is the acceleration. We know that Leroy's mass is 100kg and his deceleration is 45 m/s^2. Plugging these values into the equation, we get:

F= (100kg)(45 m/s^2) = 4500N

This means that the force of impact on Leroy is 4500N.

I hope this helps you with your homework. Remember to always use the correct equations and units when solving physics problems. Keep up the good work!

Sincerely,

Scientist