Magnitude of Average Acceleration

AI Thread Summary
To find the magnitude of average acceleration of a Super Ball rebounding off a wall, the initial velocity is 27.0 m/s, and the final velocity is -15.0 m/s (negative due to direction change). The contact time with the wall is 4.50 ms, which is converted to 0.0045 seconds. Using the formula for average acceleration, a = (vf - vi) / t, the calculation yields a value of -9333.33 m/s², which is approximately 9333.33 m/s² when considering magnitude. The discussion highlights the importance of correctly applying the formula and understanding the direction of velocity changes.
jets29
Messages
2
Reaction score
0
A 50.0 g Super Ball traveling at 27.0 m/s bounces off a brick wall and rebounds at 15.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 4.50 ms, what is the magnitude of the average acceleration of the ball during this time interval?

I can't seem to get this problem right. Initially i converted 4.5ms to .0045s. Then I chose a time such as 4s to determine a distance and have a time perspective. I then multiplied 27x4 to determine the distance and got 108m, Then I determined the time it would take for the ball to return and got 7.2s. Then I used all this info with the .0045 included in the total time to calculate the average acceleration= (vf-vi)/(tf-ti). when everything was plugged in, (15-27)/(11.2045-0)=1.071m/s^2(assuming the absolute value is what they want when they say magnitude)
This is wrong. Any help will do thanks.
 
Last edited:
Physics news on Phys.org
never mind i got it
 
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