# Pulleys/Static equilibrium

## Homework Statement

Find the mass m of the counterweight needed to balance the 1600 kg truck on the incline. Assume all pulleys are frictionless and massless.

Picture attached

## Homework Equations

Conditions for static equilibrium so that angular acceleration=0:
$$\sum$$Torque=0

## The Attempt at a Solution

We're learning about rotational dynamics and torque and I honestly cannot make the connection between that and this problem. Please help ):

#### Attachments

• p10-32alt.gif
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## Answers and Replies

tiny-tim
Science Advisor
Homework Helper
Welcome to PF!

Find the mass m of the counterweight needed to balance the 1600 kg truck on the incline. Assume all pulleys are frictionless and massless.

We're learning about rotational dynamics and torque and I honestly cannot make the connection between that and this problem. Please help ):

Hi xdevinx! Welcome to PF!

I can't see the diagram yet, but if this is a standard weight-pulley-weight problem, then rotational dynamics and torque and irrelevant …

just call the tension T, and use good ol' Newtons second law twice (once on each weight).