Question
Which statements describe a situation in which work is being done? Select three options.
A mover carries a box up a flight of stairs.
A mover carries a box across a room.
Wind blows against a steel table anchored to the ground.
Wind blows a pool chair across the yard.
A weightlifter lifts a barbell off the ground.
A weightlifter holds a barbell above the head.
A mover carries a box up a flight of stairs.
A mover carries a box across a room.
Wind blows against a steel table anchored to the ground.
Wind blows a pool chair across the yard.
A weightlifter lifts a barbell off the ground.
A weightlifter holds a barbell above the head.
Answers
GPT-4o mini
To determine whether work is being done in each situation, we consider the physics definition of work, which states that work is done when a force causes an object to move in the direction of that force. Here are the three correct statements from your options:
1. **A mover carries a box up a flight of stairs.** (Work is done as the box is moved against the force of gravity.)
2. **Wind blows a pool chair across the yard.** (Work is done because the wind exerts a force on the chair, causing it to move.)
3. **A weightlifter lifts a barbell off the ground.** (Work is done as the weightlifter exerts an upward force to raise the barbell against the force of gravity.)
The other options do not involve movement or significant force in the direction of movement. For example, carrying a box across a room does involve movement, but if the box is being carried at a constant height (no vertical work done) and the force exerted vertically does not equal the horizontal movement, it may not meet the strict definition of work in terms of net movement concerning force. Holding a barbell above the head also does not constitute work since there is no movement of the barbell in that case, despite the force applied.
1. **A mover carries a box up a flight of stairs.** (Work is done as the box is moved against the force of gravity.)
2. **Wind blows a pool chair across the yard.** (Work is done because the wind exerts a force on the chair, causing it to move.)
3. **A weightlifter lifts a barbell off the ground.** (Work is done as the weightlifter exerts an upward force to raise the barbell against the force of gravity.)
The other options do not involve movement or significant force in the direction of movement. For example, carrying a box across a room does involve movement, but if the box is being carried at a constant height (no vertical work done) and the force exerted vertically does not equal the horizontal movement, it may not meet the strict definition of work in terms of net movement concerning force. Holding a barbell above the head also does not constitute work since there is no movement of the barbell in that case, despite the force applied.