Posted by **Dani** on Tuesday, March 13, 2012 at 5:29pm.

In this problem they show a diagram of a pulley system with an inclined plane (25 degree incline). There is a box called m1=47kg resting on the incline plane and m1=35kg hanging on the vertical line. The question reads: The coefficient of friction between m1 and the surfvace of the inclined plane are Ustatic=0.42 and Ukinetic=0.19.

a)if the masses are held in place and then released , will they start to move? ------> I know the answer is NO.

b)how much mass would you have to add to m2 to cause the masses to begin to move? ----> The answer should be 2.8kg but I don't know how the book got this answer.

c)If you said no to a) and added the mass that you calculated in b), what would be the acceleration of the masses? ---> answer given in the back of textbook is 5.7 m/s^2

ANY help with this problem would be greatly appreciated!! THANK YOU SO MUCH in advance :)

- Physics -
**Henry**, Wednesday, March 14, 2012 at 9:46pm
W1 = m1g = 47kg * 9.8N/kg = 461 N

W2 = m2g = 35kg * 9.8N/kg = 343 N.

F1 = 461N @ 25 Deg.

Fp = 461*sin25 = 195 N.=Force parallel

to the incline.

Fv = 461*cos25 = 418 N. = Force perpendicular to incline.

Fn = F2 - Fp - Fs.

Fn = 343 - 195 - 0.42*418 = 0.

Fn = 343 - 195 - 176 = -28 N.

a.No, the masses would not move, because the opposing force is 28 N greater than F2. Therefore we must add

28 N. to F2:

b. mg = 28 N.

m = 28/g = 28 / 9.8 = 2.86 kg added.

- Physics -
**anonymous**, Thursday, March 15, 2012 at 10:13am
thank you very much! and to find the acceleration would it just be Fnet=ma and solve for a... Fnet=Fg-Ff?

## Answer This Question

## Related Questions

- Physics - grade12 - In this problem they show a diagram of a pulley system with ...
- physics grade 12 - In this problem they show a diagram of a pulley system with ...
- Physics - An inclined plane is on a table 1.4m tall. A 6kg box is hanging ...
- Physics - A 42-kg box slides down a frictionless inclined plane. The angle of ...
- AP Physics - Two blocks are connected by a string over a frictionless, massless ...
- College Physics - A box with a mass of 3.5 kg is resting on a horizontal ...
- Physics - A 3.3 kg wooden block is placed on 22 degree inclined plane and is ...
- physics - A 3.3 kg wooden block is placed on 22 degree inclined plane and is ...
- Physics - In the figure, a 6-kg box is sliding up an incline that makes an angle...
- physics - Two blocks are connected by a string over a frictionless, massless ...

More Related Questions