Time for a cyclist to stop moving if he stops pedalling

  • Thread starter bathmecheng
  • Start date
  • Tags
    Time
In summary, the problem involves calculating the distance traveled by a bicycle when the rider stops pedalling from an initial speed of 2m/s. The mass of the rider is 60kg and the mass of the bicycle is 7kg. The drag is given by 7.5V^2, where V is the velocity, and the slope is 10 degrees. To find the deceleration, the formula F=ma is used, but it is noted that the drag decreases with the decrease in velocity, making the deceleration not constant. An integral must be used to solve the problem, and the final formula is x(t) = xo + v0t - (7.5/m)* (V2-V20
  • #1
bathmecheng
1
0

Homework Statement



If the rider stops pedalling calculate the distance traveled by the bicycle before it comes to rest from an initial speed of 2m/s.

Mass of rider: 60kg
Mass of bicycle: 7 kg
Drag: 7.5 V^2 (where V is the velocity)
Slope : 10°

The Attempt at a Solution



F= ma
-7.5V^(2) - sin10° mg = ma to find the deceleration

however I know that the drag decreases with the decrease in velocity, hence the deceleration is not constant! I think I should use some sort of integral! HELP!sorry guys I found the formula I was looking for derived by my lecturer!
 
Last edited:
Physics news on Phys.org
  • #2
x(t) = xo + v0t - (7.5/m)* (V2-V20) + (m*g/7.5)*ln(V/V0)where m= mass of the system, V0 = initial velocity, V = final velocity. so since V= 0 at the end x(t) = xo + v0t - (7.5/m)* (V2-V20) + (m*g/7.5)*ln(V/V0)x(t) = xo + 2t - (7.5/67)* (0-22) + (67*9.8/7.5)*ln(0/2) x(t)= xo + 2t - 3.77 + 4.63 x(t) = xo + 6.4 t since xo = 0 x(t)= 6.4 t distance travelled = 6.4 * time taken to come to rest
 

1. How does a cyclist's speed affect the time it takes for them to stop moving if they stop pedalling?

The faster a cyclist is moving, the longer it will take for them to come to a complete stop if they stop pedalling. This is because the momentum of their forward motion will carry them for a longer distance before they come to a standstill.

2. Does the weight of the cyclist's bike affect the time it takes to stop moving?

Yes, the weight of the cyclist's bike will affect the time it takes for them to stop moving if they stop pedalling. A heavier bike will have more momentum and will take longer to come to a stop compared to a lighter bike.

3. How does the terrain affect the time it takes for a cyclist to stop moving if they stop pedalling?

The terrain can have a significant impact on the time it takes for a cyclist to stop moving if they stop pedalling. On a flat, smooth surface, a cyclist can stop relatively quickly. However, on a steep incline, it will take longer for them to come to a complete stop as they will have to fight against the force of gravity.

4. Can the cyclist's braking technique affect the time it takes to stop moving?

Yes, a cyclist's braking technique can affect the time it takes for them to stop moving if they stop pedalling. Applying the brakes gently and evenly can help to slow down the bike gradually, resulting in a shorter stopping distance. However, if the brakes are applied suddenly and harshly, the bike may come to a stop more quickly, but there is a higher risk of losing control.

5. Does the cyclist's body position affect the time it takes for them to stop moving if they stop pedalling?

Yes, the cyclist's body position can affect the time it takes for them to stop moving. If the cyclist leans forward and lowers their center of gravity, they may be able to stop more quickly as this will help to slow down the bike's forward momentum. However, if the cyclist is in an upright position, it may take longer for them to come to a stop as they will have less control over the bike.

Similar threads

  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
3K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
20
Views
2K
Replies
13
Views
664
Replies
1
Views
2K
Replies
1
Views
958
  • Introductory Physics Homework Help
Replies
6
Views
2K
Back
Top