A net force of 12.0 N causes an object to increase its speed from 15.0 m/s to 18.0 m/s during a 2.0 second interval. What is the mass of the object?

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.