Energy, Power, Work related question

AI Thread Summary
The discussion revolves around a physics problem involving a pitcher rotating a 0.25kg ball in a vertical circular path before release. Key calculations involve kinetic energy (KE) and potential energy (PE) to determine the speed of the ball at release. The initial equations provided are correct, but there is a mention of the work done by the pitcher, which is crucial for accurate calculations. The conversation highlights the importance of considering all forces and energy transformations in the problem. Overall, the focus is on clarifying the calculations to find the correct speed upon release.
alevis
Messages
17
Reaction score
0
This isn't the actual problem given in the assignment. I've twisted it a bit because I want to see were I specifically go wrong in my calculations.
1. A pitcher rotates a 0.25kg ball around a vertcal circular path of radius 0.6m before releasing it. The pitcher exerts a 50N force directed parallel to the motion of the ball around the complete circular path. The speed of the ball at the top of the circle is 20m/s. If the ball is released at the bottom of the circle, what is the speed upon release?



2. KE = 1/2mv^2
PE = mgh
Energy at top = Energy at bottom.
1/2mvi^2+mgh = 1/2mvf^2+mgh.


3.vf = sqrt (1/2mvi^2+mgh-mgh)/m
 
Physics news on Phys.org
Welcome to PF!

Hi alevis! Welcome to PF! :smile:
alevis said:
A pitcher rotates a 0.25kg ball around a vertcal circular path of radius 0.6m before releasing it. The pitcher exerts a 50N force directed parallel to the motion of the ball around the complete circular path. The speed of the ball at the top of the circle is 20m/s. If the ball is released at the bottom of the circle, what is the speed upon release?
…
3.vf = sqrt (1/2mvi^2+mgh-mgh)/m

What about the work done by the pitcher? :wink:

(and you're missing a 2)
 
thanks alot
 

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 'Collision of a bullet on a rod-string system: query'

Thread 'Collision of a bullet on a rod-string system: query'

In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
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

Conservation of energy problem: Ball rolling down inclined plane and then through a loop-the-loop
Replies
10
Views
2K
Vertical Circular motion- A confusing question
Replies
29
Views
407
A block dropping onto a spring system
2
Replies
58
Views
2K
Catapult spring, Kinetic and Potential energy
Replies
10
Views
3K
Help with a work/kinetic energy/potential energy problem
Replies
49
Views
4K
Energy and momentum conservation
Replies
6
Views
2K
Maximum Height of Ball on U-Shaped Ramp
Replies
17
Views
2K
Question about springs and rotational/translational energy
Replies
4
Views
1K
Homework help: Work and Energy: Spring
Replies
3
Views
1K
Energy Equation for a Roller Coaster on a Full Circular Loop
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top