my answer for these are 1. a 2.c 3 d but not sure so please anyone see if i am correct
1. In which of the following cases is work done on the object?
A. Lifting an object off the floor.
B. Pushing an object, but it does not move
C. Carrying an object at a constant velocity
D. None of these
2. The energy of a system increases when
A. a force is applied to it
B. it does work on the environment
C. The environment does work on it.
D. None of these
3. The energy of a system decreases when
A. it does work on the environment
B. a force is applied to it
C. the environment doe work on it
D. none of these
Iwould go 3A. Others right.
To determine if your answers are correct, let's go through each question and explain the reasoning behind the correct answer:
1. In which of the following cases is work done on the object?
A. Lifting an object off the floor.
To determine if work is done on the object, we need to consider the definition of work. Work is defined as the product of force and displacement. In this case, when you lift an object off the floor, you are exerting a force (upward) and the object is displaced in the same direction. Therefore, work is done on the object.
B. Pushing an object, but it does not move.
In this case, the object does not move, so there is no displacement. Since work is the product of force and displacement, if the displacement is zero, then no work is done on the object.
C. Carrying an object at a constant velocity.
When you carry an object at a constant velocity, you are exerting a force to counteract the force of gravity. However, because the object is not changing its position (velocity is constant), there is no displacement. Therefore, no work is done on the object.
D. None of these.
Since we have identified that work is done in case A (lifting an object off the floor), the correct answer is not D (None of these).
Based on our explanation, the correct answer for question 1 is A. Lifting an object off the floor.
Now let's move on to question 2:
2. The energy of a system increases when:
A. A force is applied to it.
When a force is applied to a system, it may cause a change in the system's energy. However, it is important to note that applying a force does not necessarily guarantee an increase in energy. Other factors, such as displacement, need to be considered. Therefore, A is not necessarily the correct answer.
B. It does work on the environment.
When a system does work on the environment, it transfers energy from the system to the surroundings, resulting in a decrease in the system's energy. Therefore, B is not the correct answer.
C. The environment does work on it.
When the environment does work on a system, it transfers energy from the surroundings to the system, which results in an increase in the system's energy. Therefore, C is the correct answer.
D. None of these.
Since we have identified that an increase in energy occurs when the environment does work on the system, the correct answer is not D (None of these).
Based on our explanation, the correct answer for question 2 is C. The environment does work on it.
Now let's move on to question 3:
3. The energy of a system decreases when:
A. It does work on the environment.
When a system does work on the environment, it transfers energy from the system to the surroundings, resulting in a decrease in the system's energy. Therefore, A is the correct answer.
B. A force is applied to it.
When a force is applied to a system, it may cause a change in the system's energy. However, it is important to note that applying a force does not necessarily guarantee a decrease in energy. Other factors, such as displacement, need to be considered. Therefore, B is not necessarily the correct answer.
C. The environment does work on it.
When the environment does work on a system, it transfers energy from the surroundings to the system, which results in an increase in the system's energy. Therefore, C is not the correct answer.
D. None of these.
Since we have identified that a decrease in energy occurs when the system does work on the environment, the correct answer is not D (None of these).
Based on our explanation, the correct answer for question 3 is A. It does work on the environment.