# Mechanics Pulleys HELP!! I keep getting the wrong answer...Watch

#1
part 2c : I got 3.98 both times I did this but apparently the answers 4.67? I don’t understand what I’m doing wrong.
0
1 week ago
#2
(Original post by alevels2020)
part 2c : I got 3.98 both times I did this but apparently the answers 4.67? I don’t understand what I’m doing wrong.
I haven't checked the whole thing in detail, but it looks like you're still using the same acceleration for Q before and after P hits the ground.

Before P hits the ground, the acceleration is due to the effects of gravity and the tension in the string. But after P hits the ground, the string goes slack. You have to do the second SUVAT calculation with a different value of a.
2
#3
(Original post by Pangol)
I haven't checked the whole thing in detail, but it looks like you're still using the same acceleration for Q before and after P hits the ground.

Before P hits the ground, the acceleration is due to the effects of gravity and the tension in the string. But after P hits the ground, the string goes slack. You have to do the second SUVAT calculation with a different value of a.
ahh ok thank you so much
0
1 week ago
#4
(Original post by alevels2020)
ahh ok thank you so much
Also, for the last bit you did 2 + 1.98, it would be 2 + 2 + 1.98 as the particle has moved up 2m once and 2m again. Also you should have got s = 0.667 for the last bit, you then do 2 + 2+ 0.667 = 4.67 (3 s.f.).

Hope this helps
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