Ivan exerts 20 N of force to lift a basket 2 m. He then carries the basket 5 m across a room to place it on a shelf. Ivan does work when he . The amount of work he does is .
Explanation :
It is given that,
Force acting on Ivan, \(F=20\ N\)
Height of the basket above the ground, s = 2 m
Work done in this case would be :
\(W=Fs\ cos\theta\)
Where
\(\theta\) is the angle between the force and the displacement and it is equal to 0.
So, \(W=20\ N\times 2\ m\)
\(W=40\ J\)
Ivan does work when he lifts the basket and it is equal to 40 J.
When he carries the basket 5 m across a room to place it on a shelf, then his weight is acting vertically downwards. The angle between the force and the displacement is now 90.
So, the work done he does is 0.