Work is defined as a force applied to an object that causes it to move over a distance. In mathematical terms, work (W) is calculated as the product of the force (F) applied in the direction of displacement (s) and the displacement itself:
W = F • s
For work to be done, there must be displacement of the object in the direction of the force.
Let's consider each situation:
A. Jessica pushes a 25 kilogram cart a distance of 10 meters.
Jessica is pushing the cart and causing it to move over a distance of 10 meters. Since there is a force applied by Jessica that results in the displacement of the cart, work is being done.
B. Bane carries a 20 kilogram box a distance of 50 meters.
Bane is carrying a box and moving it over a distance of 50 meters. Just like Jessica with the cart, Bane is applying a force that causes the box to be displaced over a distance, and thus work is being done.
C. A weightlifter holds a 100 kilogram barbell over his head.
The weightlifter is holding the barbell steady, which means there is no displacement of the barbell while he is holding it. Even though he is applying an upward force, because there is no movement in the direction of that force (the displacement is zero), no work is being done.
D. Ali is trying to push a truck away from the parking lot.
The statement only mentions that Ali is trying to push the truck; it doesn't state that the truck has moved. Without displacement, we cannot say that work is being done. Therefore, in this scenario, no work is being done unless the truck is actually moved.
E. Yana carries a 5 kilogram bag a distance of 1 kilometer.
Yana is moving the bag over a distance of 1 kilometer. There is a displacement of the bag due to the force applied by Yana, so work is being done.
Based on the definition of work being the product of force and displacement in the same direction, the correct answers are:
OA. Jessica pushes a 25 kilogram cart a distance of 10 meters.
OB. Bane carries a 20 kilogram box a distance of 50 meters.
OE. Yana carries a 5 kilogram bag a distance of 1 kilometer.
These three situations imply a force being applied to move an object over a distance, constituting work being done. The scenarios where either no displacement occurs (OC) or it is unclear if displacement occurs (OD) do not qualify as work being done according to the physics definition.
