Calculating Time and Speed of Rebounds with Coefficient of Restitution

AI Thread Summary
The discussion focuses on calculating the time taken for a ball to rebound after being dropped, considering the coefficient of restitution (e) and the effects of gravity (g). The initial rebound height is determined by the equation h = x^2/(2g), where x is the rebound speed. There is a debate about the correct application of the quadratic formula to find the time taken to reach the rebound height, with concerns raised about dimensional consistency. Participants also inquire about the speed of the ball upon its second impact and the subsequent rebound speed. The conversation emphasizes the need for accurate calculations in understanding the ball's motion and rebound behavior.
Darth Vader
Messages
1
Reaction score
0

Homework Statement


I drop a ball downwards vertically onto a smooth table. The coefficient of restitution is 0<e<1. The ball rebounds upwards vertically with speed x. What is the time taken between the time that the ball was dropped to its nth rebound?

Also, what is the time taken before the ball becomes stationary?

Homework Equations


e = speed of separation/speed of approach
Constant acceleration formulae

The Attempt at a Solution


Say the ball rises to a height h after the first rebound. Then h = x^2/(2g). The time taken to reach this height is t = x/g using the quadratic formula...
 
Physics news on Phys.org
Darth Vader said:
Say the ball rises to a height h after the first rebound. Then h = x^2/(2g).
Yes.
Darth Vader said:
The time taken to reach this height is t = x/g using the quadratic formula...
That cannot be right because the right hand side has dimension time-squared.

With what speed does it hit the floor the second time? What will be the next rebound speed?
 
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...
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...
Back
Top