please help me prepare for my final. I need to be able to understand and complete these problems to finish with a good grade in the class. Please walk me through step by step! Thank you!

A torque of $50$ J producing a counterclockwise rotation is applied to a wheel about its axle. A clockwise torque of $10\mathrm{.}0$J also acts on the axle. If the wheel moves at a rate of $2\mathrm{.}00$ rad$/$s$^2$ under the influence of these torques, what is the diameter of a $432\mathrm{.}7$g wheel. $($ consider a wheel as a disk$)$

If a sphere is released from rest at the top of a ramp $($Height$=85\mathrm{.}0$cm$),$ find the speed of the rotating sphere when it reaches the bottom

A $900$ N hiker stops $(1)/(3)$ of the way across a $3600\mathrm{.}0$ N bridge $($Length L$).$ Find the normal force acting on concrete supports at each end of the bridge.

What is the angular size $($in degrees$)$ of the moon as seen from earth?