Hi everyone, I'm new to forum and am a 3rd year university student who has never taken physics until now.. I'm currently studying for a dynamics unit test and came upon this question....(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A car whose brakes are locked skids to a stop in 70m from an initial velocity of 22.22m/s. Find the coefficient of kinetic friction.

Vi:22.22m/s

Vf:0m/s

d:70m

a(deceleration):-3.526m/s^2

g=9.81m/s^2

μ=?

2. Relevant equations

- Found deceleration using kinematics formula Vf^2=Vi^2 =2ad

- Ff= μFn

- Fg=mg

- Fnet(y)=ma ; a(up/down)=0 ; Fnet(y)=0 ; Fn-Fg=0 ; Fn=Fg

3. The attempt at a solution

In order to find Fn, in order to be able to solve for μ, I need to know the mass of the car... I have no idea where to even begin solving for the mass of the car using the currently known values :(

If anyone has time, please point me in the right direction.

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# Homework Help: Dynamics Question: Finding mass using Vi, Vf, D and acceleration

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