Why is coal costly to produce?
1.coal is found deep underground.
2. coal is expensive to make
3. coal is only found in certain places on earth.
4. coal is difficult to make in the lab.

The bar of prob. 5/82 is repeated here. the ends of the 0.4-m bar remain in contact with their re- spective support surfaces. end b has a velocity of 0.5 m/s and an acceleration of 0.3 m/s2 in the di- rections shown. determine the angular accelera- tion of the bar and the acceleration of end a.