Missed my class and don't know how to even begin.

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The discussion revolves around a physics problem involving a 100kg bicycle and rider skidding to a stop on a 15-degree hill. The user is struggling to understand how to apply the coefficient of friction and the relevant equations due to missing class. Key points include calculating the forces acting on the bike, specifically friction and gravitational forces, to determine acceleration. The user has made an attempt to solve for time and distance but is unsure about the correctness of their calculations. Guidance is provided on using kinematic equations to find the required values, emphasizing the importance of understanding the forces involved.
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Homework Statement



a 100kg bicycle and rider initially move at 16 m/s up a 15 degree hill. The rider slams on the brakes and skids to rest. The coefficient of friction is (0.8, 0.7)

Homework Equations


I have a few but nothing to do with a coefficient of friction.
The last ones given to me where like
MVi + ƩF(Δt) = MVf

The Attempt at a Solution


I can' make any since I was sick for class. I'm sure the professor was supposed to give at least a hand out with some explanation. So could someone at least give me a idea what I have to look up online that will help me get started on this problem?
 
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What exactly are you trying to solve for? I'm guessing time?
 
Gehh sorry. Why do I keep forgetting that?
a. How far does the bike skid?
b. What was the elapsed time before the bike stops skidding?
 
This is what I have to help so far.

(100kg)(16m/s) + ƩF(Δt) = 0

ƩF = (-mg sin(15) + uFn)
→ƩF = (-9.8 x 100kg x sin(15)) + u( 100 x 9.8 x cos 15)

→ƩF = -1232.877407

(100kg)(16m/s) + (-1232.877407)(Δt) = 0

1600 = (1232.877407)(Δt)

Δt = 2.59

I'm not sure if it is right, I might have forgotten a few things. Mainly...how to find ƩF

Please correct me! I'm only a freshman.
 
Last edited:
Hi,
The basics are, 2 forces act on the bike:-
Friction=Normal force * coefficient of KINETIC friction = (mg cosθ)*k
gravitational force=mg sinθ

From this info, find acceleration

use v2-u2 =2as to find distance
use v=u+at to find time.

I'm not sure there are no other factors. Pls check!
 

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