Exam 4 Preap Physics Numbers 1-5

1. 1.Which of the following sentences uses work in the scientific sense?

A. Stan goes to work on the bus.

B. Anne did work on the project for 5 hours.

C. Joseph found that holding the banner in place was hard work.

D. An engine does work on a car when the car is moving.

This sentence uses the term "work" in the scientific sense because it refers to the concept of work as defined in physics, where work is done when a force is applied to an object and it is displaced in the direction of the force. In this case, the engine applies a force to the car, causing it to move, which is an example of work being done.

Explanation

This sentence uses the term "work" in the scientific sense because it refers to the concept of work as defined in physics, where work is done when a force is applied to an object and it is displaced in the direction of the force. In this case, the engine applies a force to the car, causing it to move, which is an example of work being done.

2. 4. In which of the following sentences is work used in the scientific sense of the word?

A. Holding a heavy box requires a lot of work.

B. A scientist works on an experiment in the laboratory.

C. Sam and Rachel pushed hard, but they could do no work on the car.

D. John learned that shoveling snow is hard work.

not-available-via-ai

Explanation

not-available-via-ai

3. 2. Work is done on an object

A. whenever a force acts on the object.

B. whenever a force is perpendicular to the displacement of the object.

C. whenever a force causes a displacement of the object.

D. whenever a net force acts on the object.

Work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. Therefore, work is only done when a force causes a displacement of the object. If a force is applied but there is no displacement, no work is done. So, option c is the correct answer.

Explanation

Work is defined as the product of the force applied on an object and the displacement of the object in the direction of the force. Therefore, work is only done when a force causes a displacement of the object. If a force is applied but there is no displacement, no work is done. So, option c is the correct answer.

4. 5. In which of the following sentences is work used in the everyday sense of the word?

A. Lifting a heavy bucket involves doing work on the bucket.

B. The force of friction usually does negative work.

C. Sam and Rachel worked hard pushing the car.

D. Work is a physical quantity.

In sentence c, "worked" is used in the everyday sense of the word, referring to the physical activity of Sam and Rachel pushing the car. The other sentences use "work" in a more technical or abstract sense, such as the concept of work in physics (sentence d) or the force of friction doing negative work (sentence b). Sentence a also refers to work in a technical sense, as it describes doing work on an object.

Explanation

In sentence c, "worked" is used in the everyday sense of the word, referring to the physical activity of Sam and Rachel pushing the car. The other sentences use "work" in a more technical or abstract sense, such as the concept of work in physics (sentence d) or the force of friction doing negative work (sentence b). Sentence a also refers to work in a technical sense, as it describes doing work on an object.

5. 3. In which of the following cases is no work done?

A. A weightlifter lifts a barbell.

B. A weightlifter holds a barbell overhead.

C. A weightlifter slowly lowers a barbell.

D. A weightlifter drops a barbell and the barbell falls to the ground.

When a weightlifter holds a barbell overhead, no work is done because work is defined as the product of force and displacement in the direction of the force. In this case, the weightlifter is applying a force to hold the barbell, but there is no displacement in the direction of the force. The barbell is not moving vertically, so no work is being done on it.

Explanation

When a weightlifter holds a barbell overhead, no work is done because work is defined as the product of force and displacement in the direction of the force. In this case, the weightlifter is applying a force to hold the barbell, but there is no displacement in the direction of the force. The barbell is not moving vertically, so no work is being done on it.