Identify the type of machine and explain your reasoning. If the machine and explain your reasoning.

Can you pleas help me with those questions.
16. Identify the type of machine and explain your reasoning. If the machine and explain your reasoning. If the machine is a level identify the class of lever.
a)      Letter opener
b)     A wheelchair access ramp
c)      An oar in a rowboat
d)     A nutcracker designed with its hinge at one end, nut in the middle, and grip at the other end
17. Consider the following compound machines, identify two types of simple machines used for each.
a)      Your mouth biting into an apple (including the jawbone and front teeth)
b)     A tricycle
18. Find the unknown quantity asked for each of the following situations.
a)      Find the magnitude of the force applied perpendicular to a lever if the force is applied 2.2m from the pivot point exerting 55 Nm of torque. 
b)     Find the distance of the force to the pivot if a force of 14N exerts a torque of 49 Nm on a large gate.