Your friend’s car has died and needs to be pushed off the road. The car is sitting on a smooth road, and after it is moving you will push it on to a smooth paved shoulder. Which of the following statements is true about the forces involved in moving the car?

Question

(1 point)
Responses

It requires less force to start a stopped car moving on smooth surface than to keep the car moving onto a smooth surface of the shoulder.
It requires less force to start a stopped car moving on smooth surface than to keep the car moving onto a smooth surface of the shoulder.

It requires an equal amount of force to start the stopped car moving on a smooth and to keep the car moving on a smooth surface.
It requires an equal amount of force to start the stopped car moving on a smooth and to keep the car moving on a smooth surface.

It requires more force to start a stopped car moving on smooth surface than to keep the car moving onto a smooth surface of the shoulder.
It requires more force to start a stopped car moving on smooth surface than to keep the car moving onto a smooth surface of the shoulder.
Question 2
Your friend’s car died again and needs to be pushed off of the road. This time however, the road where it stopped is smooth, but the shoulder is muddy and full of holes and gravel. Which of the following is true about the forces involved in moving the car this time?(1 point)
Responses

It requires an equal amount of force to start the stopped car moving on a smooth and to keep the car moving on the very rough surface of the shoulder.
It requires an equal amount of force to start the stopped car moving on a smooth and to keep the car moving on the very rough surface of the shoulder.

It requires less force to start a stopped car moving on smooth surface than to keep the car moving on the very rough surface of the shoulder.
It requires less force to start a stopped car moving on smooth surface than to keep the car moving on the very rough surface of the shoulder.

It requires more force to start a stopped car moving on smooth surface than to keep the car moving on the very rough surface of the shoulder.
It requires more force to start a stopped car moving on smooth surface than to keep the car moving on the very rough surface of the shoulder.
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Answer 1

Let's analyze both questions separately.

Question 1:

1. It requires less force to start a stopped car moving on a smooth surface than to keep the car moving onto a smooth surface of the shoulder.

   • This statement is false. Starting a car from rest usually requires more force compared to maintaining motion once it's moving, due to overcoming static friction.

2. It requires an equal amount of force to start the stopped car moving on a smooth surface and to keep the car moving on a smooth surface.

   • This statement is false. The force needed to overcome static friction when starting the car is typically greater than the force needed to maintain motion once it is moving.

3. It requires more force to start a stopped car moving on a smooth surface than to keep the car moving onto a smooth surface of the shoulder.

   • This statement is true. As mentioned, starting the car involves overcoming static friction, which is generally higher than the kinetic friction once the car is in motion.

Answer for Question 1:

It requires more force to start a stopped car moving on a smooth surface than to keep the car moving onto a smooth surface of the shoulder. (This is the correct statement.)

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Question 2:

1. It requires an equal amount of force to start the stopped car moving on a smooth surface and to keep the car moving on the very rough surface of the shoulder.

   • This statement is false. The rough surface will introduce additional friction, which means it will require different forces to maintain motion.

2. It requires less force to start a stopped car moving on a smooth surface than to keep the car moving on the very rough surface of the shoulder.

   • This statement is true. Once the car is moving on a rough surface, the friction and resistance will likely be greater than starting it on a smooth surface.

3. It requires more force to start a stopped car moving on a smooth surface than to keep the car moving on the very rough surface of the shoulder.

   • This statement is false. It would be easier to start the car moving on a smooth surface than to keep it moving in a rough environment.

Answer for Question 2:

It requires less force to start a stopped car moving on a smooth surface than to keep the car moving on the very rough surface of the shoulder. (This is the correct statement.)

In summary:

• For Question 1, the true statement refers to the force needed when starting versus maintaining motion on a smooth surface.
• For Question 2, the true statement compares the forces needed on a smooth surface against a rough surface.