Has anyone done Q3 on the M4 Mock Paper? I keep getting the negative of what I'm supposed to get in the show that...
Attachment not found
Your diagram is incorrect as you have assumed that it rebounds backwards but in fact it does not. I believe the equations should look like x+y=ucos(30) y−x=eucos(30) Due to this assumption the tan function yields the negative version of the answer. The angle theta is 90 degress round from where you have it and measured from the horizontal.
Your diagram is incorrect as you have assumed that it rebounds backwards but in fact it does not. I believe the equations should look like x+y=ucos(30) y−x=eucos(30) Due to this assumption the tan function yields the negative version of the answer.
Couldn't the converse be argued though, that if you assume it doesn't rebound backwards it could?
How do you know for sure it doesn't rebound backwards?
edit: Also if the angle is greater than 120 degrees which would be the condition for the ball to not rebound backwards, the tangent function would need to be negative as tangent of an angle greater than 120 and less than 180 would be negative which isn't possible with the show that unless e>5/3?
Couldn't the converse be argued though, that if you assume it doesn't rebound backwards it could?
How do you know for sure it doesn't rebound backwards?
The issue is you have measured the wrong angle primarily. The assumption that it travels backwards is not the most important bit. You have measured theta from the negative direction of the velocity and not the positive end. I will post a diagram.
Note how theta has been measured. The angle is measured as of the velocity carried on past the collision. So it is easier to assume that it does not rebound.
Note how theta has been measured. The angle is measured as of the velocity carried on past the collision. So it is easier to assume that it does not rebound.