A0.320 kg pendulum bob passes through the lowest part of its path at a speed of 2.76 m/s. what is the tension in the pendulum cable at this point if the pendulum is 79.2 cm long?

Ke reqd to move from 0 to 50 will be proportional to 50x50 or 2500. this is equal to w.  to change vel from 50 to 150 you need energy prop to 22500 - 2500 = 20,000. this corresponds to 8w.  best answer is a) . work reqd is prop to velocity squared. 

They all deal with hard evidence(scientific)

The inference is supported by evidence in the graph is this is an exothermic reaction where the total release of energy equals a + c.