# Calculating minimum force

1. A 1 tonne rock is being dragged up a 30 degree slope using the a pulley system.
If there is a constant resistance to movement between the rock and the ground of 350N, calculate the minimum force necessary to drag the rock up the slope.

2.

3. All i got so far is

1t = 1000kg

1000kg x 9.8 (gravity)
=9800N
Acting upon the slope from the rock

## Answers and Replies

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Set up a free body diagram to find the forces acting on the rock.

Thanks
Matt

tiny-tim
Homework Helper
Hi vbillej!
3. All i got so far is

1t = 1000kg

1000kg x 9.8 (gravity)
=9800N
Acting upon the slope from the rock
No, that's wrong …

9800N is the force of gravity on the rock.

There are four forces on the rock … gravity, normal force, friction force (= 350N), and the force from the rope.

As CFDFEAGURU says, set up a free body diagram.

Thanks both of you for your replies

Hi vbillej!

9800N is the force of gravity on the rock.

.
Yes i forgot its actually the weight from the rock, thanks for reminding me