Mechanics Paper 5 2015. Post your Problems here!!

[nighthawk]

Hey guys, shoot any problems in the mechanics paper if you have. Lets try to solve it together.

 

[nighthawk]

Wow. Nobody has any problem. Then I guess tomorrow is going to be a good day guys. All the best.

 

[Pink Flower]

When the string is slack, GPE=0 right?

 

[nighthawk]

No EPE is zero

 

[PlutoHuman]

Can someone do this please?

 

[nighthawk]

Which year is this? Can you please tell me the answers. I solved it. Just want to make sure everything is all right.

PlutoHuman

 

[nighthawk]

Well, I got this:

i) 0.700
ii) 37.3 N

Are they correct?

 

[TheJDOG]

Well, I got this:

i) 0.700
ii) 37.3 N

Are they correct?

Yes

 

[nighthawk]

So this is how you should do it.

The first one is easy. Just use the center of mass formula. and in the second one, you will have to find out the center of mass of the lamina first. Then, you will have to combine the center of mass of the lamina and center of mass of the frame and divide it by the total weight (where the weight of the lamina is x) . By trigonometry, you can find out the center of mass of the resulting solid. Then, use this value in the center of mass formula and find out X, which is the weight of the required frame) . Hope this helps. Please do ask me if you need elaboration.

 

[Abdel Moniem]

http://freeexampapers.automaticpapers.com/as-a-level/mathematics-9709/9709_s13_qp_51.pdf
Q7