# force on a pulley???

• Sep 11th 2008, 12:13 PM
Im doin My best!
force on a pulley???
a particle of mass 10kg is at rest on a plane inclined at an angle tan-1(3/4) to the horizontal.contact is rough with a coefficient of friction of 0.25.it is connected by means of a light inextensible string passing over a smooth,fixed pulley to a second particle of mass 20kg hanging freely.

(i) i worked the acceleration out to be 2g/5 (g=9.8)

(ii) i then worked out the tension in the string to be 12g Newtons

(iii)FIND THE FORCE ON THE PULLEY? how do i work this out? what is the formula?

can someone please solve part (iii).
• Sep 11th 2008, 12:45 PM
topsquark
Quote:

Originally Posted by Im doin My best!
a particle of mass 10kg is at rest on a plane inclined at an angle tan-1(3/4) to the horizontal.contact is rough with a coefficient of friction of 0.25.it is connected by means of a light inextensible string passing over a smooth,fixed pulley to a second particle of mass 20kg hanging freely.

(i) i worked the acceleration out to be 2g/5 (g=9.8)

(ii) i then worked out the tension in the string to be 12g Newtons

(iii)FIND THE FORCE ON THE PULLEY? how do i work this out? what is the formula?

can someone please solve part (iii).

The force acting on the pulley will be the vector sum of the two tensions acting at the pulley. So one tension is pulling straight down and a tension of equal magnitude is pulling down the slope.

-Dan