
#1
Dec2512, 02:06 AM

P: 2

Can some one please tell me the equation needed to caculate the torque needed 1. to overcome gravity trying to make you roll down hill and 2. ride up hill at 10km/h for a 100kg (bike & rider) on a bike with 66cm wheels on a 10' slope?
cheers stan 



#2
Dec2512, 09:20 AM

Mentor
P: 10,853

Is this homework?
1. Why do you have to overcome gravity to roll down? 2. Can you calculate the force opposite to the direction of motion? How can you use this and the wheel radius to get a torque? 



#3
Dec2512, 09:30 AM

P: 2

Yes it is home work. The reason I put in wheel diameter is that I thought the rolling resistance of the wheel along with the number of revolutions per minute and the distance per revolution might be relevant t working out the touque needed to stay at rest, not going up or down, and then the torque needed to travel up at a constant velocity?




#4
Dec2512, 09:40 AM

Mentor
P: 10,853

100kg Bike torque needed to go up 10' slope
As there is no value for the rolling resistance given, you can neglect this.
The torque needed to stay at rest is independent of rolling resistance (since there is nothing rolling). 



#5
Dec2512, 10:07 AM

Mentor
P: 11,255

Moved to the appropriate homework forum. I didn't simply delete and ask the OP to repost in the homework forum, because he's already gotten some responses. Carry on, and in the future, please post similar questions about specific exercises in the homework forums.




#6
Dec2512, 04:12 PM

P: 2,861

Draw a force diagram including the frictional force between wheel and road.
For part 1).. The bike is stationary (eg not accelerating) so what does that say about the forces acting up and down the slope? For part 2).. Perhaps think about the power required and equations relating power, torque and angular velocity. 


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