i got this questions that i couldnt solve on my own?

Question

this is my homework over weekend... i got like 10 of these questions but i need 3 of them really bad... all my friends couldnt seem to solve them...

heres the link to the photobucket

http://i129.photobucket.com/albums/p220/yollajolla/scan005.jpg

http://i129.photobucket.com/albums/p220/yollajolla/scan004.jpg

http://i129.photobucket.com/albums/p220/yollajolla/scan003.jpg

Answer 1

1st link

b) F = 40 N

c) F = 60 N

2nd link

b) linear velocity = 0.59 m/s

c) Taking g = 9.8 m/s^2

v = 0.83 m/s

d) It would not effect the answer as the expression for v which is sqrt(mu * r * g) is independent of the mass.

3rd link

a) Rotate the setup, note the reading on the balance. Find the time required for 1 circuit.

b) No work is done

c) T = 5.48 N

d) 5.9 %

e) If the cord is exactly horizontal, it won't touch the rod and hence cannot be rotated.

Answer 2

ask your teacher when you go back on monday