Rotation and power problem, help

  • Thread starter Thread starter Cyannaca
  • Start date Start date
  • Tags Tags
    Power Rotation
AI Thread Summary
The discussion revolves around calculating the power needed to lift a 15 kg bucket at a constant speed of 0.2 m/s using a winch with a radius of 0.03 m and a handle length of 0.4 m. The correct power required is identified as 29.4 W, while the user initially calculated 11.26 W. To find the necessary force, the user is advised to use the torque formula, which relates radius, force, and torque. Clarification is provided that "module" refers to the magnitude of the force. The conversation emphasizes the importance of sharing calculations for troubleshooting errors.
Cyannaca
Messages
22
Reaction score
0
Hello, I would like it if anyone could help me with this problem

A bucket of 15 kg is lifted up from a well at a constant speed of 0,2 m/s. The cord rolls up around a winch (radius 0,03m). The winch is turned with a handle 0,4m of length
a) What power is necessary bring the bucket up?
b) If the force applied is always perpendicular to the handle, what is the module of the necessary force?

The answers are 29,4 W and 11 N and I don't know what is wrong but I always get 11,26 W :mad:
 
Physics news on Phys.org
What are your calculations?
 
I finally solved a (afer half an hour!) but now I really don't know how to do b
 
"module" means the same as "magnitude".
Does that help?
 
Welcome to the forums, Cyannaca!

Can you please post your calculations, so we can help find your error? Forum rules, plus it makes it much easier for everyone.
 
Ok, so I need to use Torque= radius*F* Thank you!
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Avg Power in a Rotational Energy/Work Problem
Replies
6
Views
1K
How Do You Calculate Power in These Physics Problems?
Replies
5
Views
2K
Energy and power supplied by a bicyclist
Replies
8
Views
3K
Calculating gear ratio for vertical climb
Replies
1
Views
2K
Rotational Motion Two Questions
Replies
12
Views
4K
Rotational Mechanics question with spring
Replies
4
Views
2K
Motor calculation for a rotating platform
Replies
7
Views
5K
How does rotational motion influence static friction?
Replies
7
Views
3K
Finding Frictional Force and Power Using Work and Energy
Replies
4
Views
3K
What is the electrical power output of a turbofan engine?
Replies
16
Views
4K

Hot Threads

Recent Insights

Back
Top