# Edexcel Mechanics 2 questionWatch

#1
A cyclist starts from rest and freewheels down a hill inclined at arcsin 1/20 to the horizontal. After travelling 80 meters the road becomes horizontal and the cyclist travels a further 80 meters before coming to rest without using the brakes. The cyclist and the bike have a combined mass of 80kg. Find the resistive force (assumed constant throughout the motion).

Anyone fancy a crack at that badboy? I don't see where I'm going wrong.
0
7 years ago
#2
(Original post by SN-RAVER)
A cyclist starts from rest and freewheels down a hill inclined at arcsin 1/20 to the horizontal. After travelling 80 meters the road becomes horizontal and the cyclist travels a further 80 meters before coming to rest without using the brakes. The cyclist and the bike have a combined mass of 80kg. Find the resistive force (assumed constant throughout the motion).

Anyone fancy a crack at that badboy? I don't see where I'm going wrong.
Let the acceleration down the hill be a1 and the decceleration on the horizontal road be a2. The travelling was 80m both down the hill and on the horizontal road.
Starting from the rest and coming to the rest means that a1=a2
and a1=(F1-Fr)/m a2=Fr/m, where Fr is the resistive force (assumed constant Fr,
but really it is not).
0
X

new posts
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### University open days

• Cranfield University
Cranfield Forensic MSc Programme Open Day Postgraduate
Thu, 25 Apr '19
• University of the Arts London
Open day: MA Footwear and MA Fashion Artefact Postgraduate
Thu, 25 Apr '19
• Cardiff Metropolitan University
Sat, 27 Apr '19

### Poll

Join the discussion

#### Have you registered to vote?

Yes! (481)
37.78%
No - but I will (98)
7.7%
No - I don't want to (88)
6.91%
No - I can't vote (<18, not in UK, etc) (606)
47.6%