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CoolaTroopa
. Posts: **1,170** Senior Member

88.) Two blocks are connected by a rope that passes over a set of pulleys. One block has a weight of 412 N, and the other has a weight of 908 N. The rope and pulleys are massless and there is no friction.

(a.) What is the acceleration of the ligher block?

(b.) Suppose that the heavier block is removed and a downward force of 908 N is provided by someone pulling on the rope.

(c.) Explain why the answers in (a) and (b) are different.

I only need help with (a) and (b), I understand that the acceleration is going to be much less in (a), because the two blocks share inertia while in (b), only the smaller block remains.

But how do you calculate the acceleration in (a) and (b)?

I've been spending a long time on this problem and I would be grateful for help.

Thanks!

(a.) What is the acceleration of the ligher block?

(b.) Suppose that the heavier block is removed and a downward force of 908 N is provided by someone pulling on the rope.

(c.) Explain why the answers in (a) and (b) are different.

I only need help with (a) and (b), I understand that the acceleration is going to be much less in (a), because the two blocks share inertia while in (b), only the smaller block remains.

But how do you calculate the acceleration in (a) and (b)?

I've been spending a long time on this problem and I would be grateful for help.

Thanks!

Post edited by CoolaTroopa on

This discussion has been closed.

## Replies to: I Need Help With an AP Physics Problem.

40Junior Member774MemberAcceleration = F/m = (908-412)/ ((412+908/9.8)

(b) Total mass is now 412/9.8 kg, net force = (908-412) N. Acceleration = F/m = (908-412) / ((412/9.8))

(c) Total mass being accelerated is different in (a) and (b)

1,170Senior MemberI didn't realize that there was no need to calculate the Tension force in the problem. I spent so much time trying to calculate Tension that it stopped me from finding the answer.

Yet again, thanks!