Solving a Block and Inclined Plane Problem

[konichiwa2x]

Hi,

Can someone please expain how to do this problem? I have spent about an hour today on this can and still can't figure it out.

In the arrangement shown in the figure, a wedge of mass $$m_{3} = 3.45kg$$ is placed on a smooth horizontal surface. A small and light pulley is connected on its top edge. Two blocks having mass $$m_{1} = 1.3$$ and $$m_{2} = 1.5kg$$ are connected at the ends of the thread. $$m_{1}$$ is on a smooth horizontal surface and $$m_{2}$$ rests on inclined surface of the wedge. Base length of wedge is 2m and inclination is 37 degrees. $$m_{2}$$ is initially near the top edge of the wedge. All surfaces are smooth, g = 9.8m/s2.

http://img76.imageshack.us/img76/4812/lomyw4.png

If the whole system is released from rest, calculate

a) the velocity of the wedge when m2 reaches its bottom.
b) velcoity of m2 at that instant and tension in the thread during motion of m2.

Please help.

 

[OlderDan]

Start with a free body diagram for each block. The tension in the string is uniform, and the blocks move the same distance.

 

[kyle8921]

Hello,

I understand that this problem may seem difficult, but with some understanding of basic physics concepts and a systematic approach, you will be able to solve it. Here are the steps you can follow to solve this problem:

1. Draw a free body diagram for each individual object in the system (wedge, m1, m2).
2. Write down all the forces acting on each object (weight, normal force, friction, tension).
3. Apply Newton's second law of motion (F=ma) to each object in the system.
4. Use trigonometry to break down forces into their components (e.g. weight of m2 can be broken down into its x and y components).
5. Set up equations for each object and solve for the unknown variables (velocity, tension).
6. Check your answers by making sure they satisfy the conditions of the problem (e.g. is the velocity of m2 when it reaches the bottom of the wedge the same as the velocity of the wedge itself?).

Remember to always include units in your calculations and to double check your math. Don't get discouraged if you don't get the right answer on your first try, just keep practicing and you will get the hang of it. Good luck!