# A level Mechanics Help!!!

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#1
I was doing some practice and I stumbled upon this q and don't know how to answer it? Could anyone provide their solution thx in advance

One end of a string is attached to a small ball P of mass 4m.
The other end of the string is attached to another small ball Q of mass 3m.
The string passes over a fixed pulley.
Ball P is held at rest with the string taut and the hanging parts of the string vertical, as
shown in Figure 1.
Ball P is released
The string is modelled as being light and inextensible, the balls are modelled as particles,
the pulley is modelled as being smooth and air resistance is ignored.
(a) Using the model, find, in terms of m and g, the magnitude of the force exerted on the
pulley by the string while P is falling and before Q hits the pulley.
(8)
(b) State one limitation of the model, apart from ignoring air resistance, that will affect
(1)
0
1 year ago
#2
You need to set up two equations. Both masses are acting down, so the tensions in the string is acting up. Drawing a diagram will help. So can you find 2 equations, connecting tension? Use F = ma to help you.
1
#3
(Original post by Toast210)
You need to set up two equations. Both masses are acting down, so the tensions in the string is acting up. Drawing a diagram will help. So can you find 2 equations, connecting tension? Use F = ma to help you.
Oh ok thanks I think that makes sense I'll do that
0
1 year ago
#4
Hi, this may be a little too late, but may I ask what paper this is from? I tried this question the other day but couldn't find the entire paper for the mark schemes.
0
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