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M1 Qu.

A cyclist and her bicycle have a combined mass of 78kg. While riding on level ground and using her greatest driving force, she is able to accelerate uniformly from rest to 10ms^-1 in 15 seconds against constant resistive forces that total 60N. Her maximum driving force is 112N.

The cyclist begings to ascend a hill, inclined at an angle x to the horizontal, riding with her maximum driving force and against the same resistive forces. In this case, she is able to maintain a steady speed.

1. Find the angle x, giving your answer to the nearest degree.

_____________
I got as far as, 60 = 60 sin x. ButI think I'm wrong.

Anyone help?

Cheers
Reply 1
Avatar for adk
adk
OP
2. A large block of mass 50kg is being pulled on rough horizontal ground by means of a rope attached to the block. The tension in the rope is 200N and it makes an angle of 30 degrees with the horizontal. The coefficient of friction between the block and the ground is 0.424.

Ignoring air resistance, find the acceleration of the block.
adk
2. A large block of mass 50kg is being pulled on rough horizontal ground by means of a rope attached to the block. The tension in the rope is 200N and it makes an angle of 30 degrees with the horizontal. The coefficient of friction between the block and the ground is 0.424.

Ignoring air resistance, find the acceleration of the block.




R+ 200sin30=50x9.8
R=390N

Fric=coef of frict x R
Fric= 0.424x390=165.4N

Force= mass x acceleartion
200-165.39 = 50 x acc
a=0.69m/s^2
Reply 3
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adk
OP
tammypotato

Force= mass x acceleartion
200-165.39 = 50 x acc
a=0.69m/s^2

Is it not '200 cos 30' there, instead of just '200'?
Reply 4
adk
Is it not '200 cos 30' there, instead of just '200'?


Yeah, it should be 200cos 30.
adk
Is it not '200 cos 30' there, instead of just '200'?


yeah sorry 200cos30-165.36=50 a
a=0.157ms^-2

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