Click to open theSimulation: https://phet.colorado.edu/sims/html/balancing-act/latest/balancing-act_en.html

Instruction: Balancing torques on a seesaw

Choose "Balance Lab" tab. Don't forget to remove the supports under the board.

Select the following options in right corner of the screen: Mass Labels, Level, Rulers

For each of the given cases, balance the board at the pivot.(Do not change the location of the mass when it is assigned to a specific location)

Don't forget to convert masses to weights! Use g as 10m/s^2 (Torque = Fl and force here is the weight which is mg)

The signs of torques are assigned ascw torque is negative & ccw torqueis positive. ( You don't need to write + )

For each case, calculate total clockwise torque ( cw ), total counterclockwise torque ( ccw ) and net torque ( = cw + ccw ).

Case 1. 5 kg on right of the pivot, 10 kg on left of the pivot at 1m.

Location of 5kg brick = [1] m

cw = [2] Nm

ccw =[3] Nm

= cw+ ccw=[4] Nm

Case 2. 5 kg & 10 kg on right of the pivot, 10 kg on left of the pivot at 1m.

Location of 5kg brick = [1] m

Location of 10kg brick = [2] m

cw = [3] Nm

ccw =[4] Nm

= cw + ccw = [5] Nm

Case 3. 5 kg, 10 kg & 15 kg on right of the pivot, 20 kg on left of the pivot at 1m.

Location of 5kg brick = [1] m

Location of 10kg brick = [2] m

Location of 15kg brick = [3] m

cw = [4] Nm

ccw =[5]Nm

= cw+ccw= [6]Nm