Can someone please help me answer one of these questions

What is the role of the ocular lens?

A-of 75 cm by cm by 17.5 cm up. of is 2 kg a , in ,if it is in , kg/?

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.