An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
By the definition of work, we can work out that the work done by the force of gravity is equal to the force of gravity multiplied by the vertical displacement (since the gravity works only in the vertical direction). But in this case, it is given that the initial and final points of the path of the object lie on the same horizontal line, that means the total vertical displacement of the object thrown is zero. Mathematically, work done by gravity is expressed as, W = mgh Where, m = mass of the given object, g = acceleration due to gravity, h = Vertical height = Final height – Initial height = zero Putting all these in the equation of work, we get; W = mg × h = mg × 0 = 0 J Hence, the work done by gravity on the given object is zero joules. Therefore, the work done by gravity on the given object is zero joules, as the total vertical displacement of the object is zero.
