Thursday

April 24, 2014

April 24, 2014

Posted by **jeff** on Monday, December 8, 2008 at 12:35am.

- physics -
**drwls**, Monday, December 8, 2008 at 2:00amYou need three equations to solve for the unknown mass M and the forces at each sawhorse, F1 and F2

One of the equations is F2 = 3 F1

Another equation can be

F1 + F2 = 4 F1 = (12 + 15 + M)g

The third equation should be a moment equation. I suggest you take it about the point of contact of the sawhorse on the right.

F1*2.6 - 15g*2.0 - 12g*1.3 - Mg*0.3 = 0

You should draw yourself a figure of the loaded plank to see where the lever arm length coefficients came from.

Now you have two equations in two unknowns, M and F1. Solve for M. The g factor can be canceled out when solving for M.

**Related Questions**

physics - A bench is made of a 3 meter long plank with a mass of 12kg and 2 ...

physics - A cat walks along a uniform plank that is 4 m long and has a mass of 7...

Physics - i38. tinypic .c o m /2hnxvki .gif In the experiment, the angles ...

English Expression - Number 5, stand up. Come to the black board. Pick up a ...

Physics - Pleae help! A uniform 2m long plank is supported at each end by ropes...

physics - a plank of mass 5kg is placed on a frictionless horizontal table. ...

physics - a plank of mass 5kg is placed on a frictionless horizontal table. ...

math - If there is a bench at first and every fourth sign after that.there is ...

read and write - what part of speech is bench in this sentence? Fred gave the ...

physics - A ball with a horizontal speed of 1.25 {\rm m/s} rolls off a bench 1....