# Linear and Rotational Motion Question (really struggling)

1. Apr 28, 2010

### Dan_fitz91HNC

Linear and Rotational Motion

A load of mass 60kg is hoisted vertically by means of a light rope running over a pulley and is accelerated from 3 to 6m/s while traveling through a distance of 6 meter. If the resistance due to friction is 50N determine

A) The pulling force in the rope
B) The work done
C) Average power required to accelerate this load

So far all i have is
F=Mg-Ma=M(g-a)
Do i need to include my 50N friction resistance?

i have F=60(9.81-6)= 228.6N

For my work done i have
Work done=ForcexDistance?

Which i work out to be W.D.=(228.6+50)x6=1671.6W

For average power i have
Average power=W/t
and intera torque =Ia
However i dont know whaere to substitute in the values

Im really stuuggling with this question and its importan for me to get correct if i want to progress onto the next course. Any hints will be much appreciated.
Thankyou

2. Apr 28, 2010

### tiny-tim

Welcome to PF

Hi Dan_fitz91HNC! Welcome to PF
(where did the 6 come from? )

Sorry, but you need to be more systematic.

First, find the acceleration, using one of the standard constant acceleration formulas.

Then you can use F = ma (and yes, you have to include all the forces in F).

What do you get?