Answer: Sam provides the biggest power
Step-by-step explanation: Power is defined, in Physics, as the rate of work done. Work is energy transferred to an object due to the force causing the displacement of the object.
So, to determine Power:
For Sam:
P =



P = 50 Watts
The unit for Power is [P] = J/s = Watt
For Gary:
P =


P = 40 Watts
Comparing power of Sam and Gary, we can conclude that Sam provides the biggest power of 50 Watts.