What does this symbol mean? i need to know so i can prepare for

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.

Contains chemical energy. a. heat b. light c. natural gas

Which of the following is the largest disadvantage of about half of the electricity in the united states comes from burning