How much work is done by the force lifting a 0.1 kg hamburger vertically upward at a constant velocity of 0.3 m from a table? I thought that if it's at constant velocity, there is no work done. However all the answer choices are non-zero. Please help!
1 Answer
With the assumptions I made,
Explanation:
You said that the burger was being lifted at a "constant velocity of 0.3 m". That is the wrong units for velocity. I will assume you meant 0.3 m/s.
If the burger is moving at constant velocity, it is not accelerating. If the burger is not accelerating, the net force acting on it is zero. But that does not mean that you did not exert a force, remember the burger has weight. Gravity is exerting a force of
But, I said the net force acting on it is zero. That is true. But you are providing an upward force to keep it from falling back to the table.
#F_"net" = "weight" + "your force" = -0.98 N + "your force"
So, since
Work is force*distance. Your question did not say what the distance of the lift was. The velocity would allow us to calculate power, but the question did not ask for that. I will assume you lifted it from the table to your mouth. I will estimate the distance as 0.1 m. So the work done was
I hope this helps,
Steve
