What is the power output needed to bike uphill at a steady speed of 4.5 m/s?

  • Thread starter Thread starter Symstar
  • Start date Start date
  • Tags Tags
    Power
AI Thread Summary
To determine the power output needed for a cyclist to climb a 6.0-degree hill at a steady speed of 4.5 m/s, the cyclist's total mass is considered to be 60 kg. The initial calculation yielded a power output of 280 W based on gravitational force alone. However, it was later clarified that additional forces, such as friction or air resistance, must be accounted for when climbing uphill, which was not included in the initial assessment. This oversight led to the realization that the problem was more complex than it initially appeared. Therefore, the cyclist's actual power output required to maintain speed while climbing would be greater than the initial calculation.
Symstar
Messages
16
Reaction score
0

Homework Statement


A bicyclist coasts down a 6.0 degree hill at a steady speed of 4.5 m/s.
Assuming a total mass of 60 kg (bicycle plus rider), what must be the cyclist's power output to climb the same hill at the same speed?

Homework Equations


Newton's 1st law
P=W/t

The Attempt at a Solution


P=\frac{W}{t}=F \cdot v

Set x-axis along incline...
F-mg\sin\theta=0
F=mg\sin\theta
P=mg\sin\theta*4.5 = 276.6 W

To 2 sigfig = 280 W

Is this correct? I'm being told it is the wrong answer...
 
Physics news on Phys.org
It looks right.
Who told you that is not?
 
The site where I submit my homework =/ I can't find any problem with it either, so I don't know what's up - guess I'll go ask the professor tomorrow. Thanks for checking my work and please let me know if you do think of somewhere I went wrong.
 
Just an update... since the rider coasts down the hill but isn't accelerating, we must assume that there is a retardant force which must also be factored in when going uphill. This is where I went wrong. Kind of a trick question... blah!
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Maximum speed of car on downhill
Replies
1
Views
2K
Finding Frictional Force and Power Using Work and Energy
Replies
4
Views
3K
Power output of cyclist up slope at costant speed
Replies
7
Views
4K
Power of a bicycle accelerating up a slope.
Replies
8
Views
3K
Cyclist coasting down a hill cons. of energy
Replies
4
Views
3K
What is the power input of a motor pulling up an elevator?
Replies
3
Views
3K
Energy and power supplied by a bicyclist
Replies
8
Views
3K
How Much Power is Needed to Move an Elevator at 4.50 m/s?
Replies
11
Views
2K
Calculating Power Output for a Cyclist Coasting Down a 7.2 Degree Hill
Replies
1
Views
4K
What Is the Cyclist's Power Output to Climb a 7.0 Degree Hill at 5.0 m/s?
Replies
6
Views
28K

Hot Threads

Recent Insights

Back
Top