hey every1, any1 know how to do statics questions? i have a few virtual work questions i have to get right by 2moro or i'll fail my course! please help...

There are several engineers here who can assist.

At What point from the left end should a uniform meter stick (cg.=50 cm mark and mass=68g) be supported so that is balances 10 g a the 0 cm mark, 40g at the 30cm mark, and 60 g at the 100 cm mark.

how can I draw a free body diagram?

a shelf is supported by two posts at a distance L apart from each other. three containers , each mass M are located of (1/5)L, (2/5)L, & (3/5)L from post A.shelf has a mass of M too.Express answer in M,L,g and numerical constants...
a) Find the upward force exerted by post A on the shelf ?
pls give a support, thanks

a shelf is supported by two posts at a distance L apart from each other. three containers , each mass M are located of (1/5)L, (2/5)L, & (3/5)L from post A.shelf has a mass of M too.Express answer in M,L,g and numerical constants...
a) Find the upward force exerted by post A on the shelf ?
pls give a support, thanks

you have to sum all the forces in the y direction(M*9.8m/s). And then find the moment about point A. That will give you the reaction force at point A. Just use :
Sum of all forces in the y=0, where upward is positive
Sum of the moments about point A=0, where counter clockwise is positive.

Good luck. Let me know if it helps.

To solve the first problem about balancing a meter stick, you can use the principle of moments or torques.

First, let's draw a free body diagram. A free body diagram shows all the forces acting on an object as arrows representing the direction and magnitude of the force.

For the meter stick problem, you will have three forces: the weight of the meter stick itself, the weight of the 10g mass at the 0 cm mark, and the weight of the 40g mass at the 30 cm mark. Since the system is in equilibrium (balanced), the sum of the torques about any point should be zero.

You can take moments about the left end of the meter stick (0 cm mark). The clockwise moments should be equal to the counterclockwise moments for the system to be in equilibrium.

The weight of the stick (with its center of mass at the 50 cm mark) can be considered as a single force acting downward through the center of mass. The 10g mass at the 0 cm mark exerts a clockwise torque. The 40g mass at the 30 cm mark also exerts a clockwise torque.

Now, by using the principle of moments and setting the sum of clockwise torques equal to the sum of counterclockwise torques, you can solve for the unknown distance. Be sure to take into account the masses and their respective distances from the point of rotation.

For the second problem about the shelf and posts, you need to find the upward force exerted by post A on the shelf. To do this, you can again use the principle of moments and sum of forces in the y-direction.

First, draw a free body diagram of the system. Identify all the forces acting on the shelf, including the weight of the shelf and the weight of the three containers.

Next, consider the equilibrium condition for the system. The sum of forces in the y-direction should be zero since the system is not accelerating vertically. Set up an equation and solve for the upward force exerted by post A.

Finally, use the principle of moments to find the reaction force at point A. Sum the moments about point A and set it equal to zero since the system is in equilibrium. Solve for the reaction force exerted by post A.

Remember to consider the distances of the containers from post A and the weight of the shelf in your calculations.

By following these steps and applying the principles of equilibrium, you should be able to solve the virtual work questions. Good luck!