Key:
*** means my answer
1. If the net force on an object is 0 N, the forces are considered unbalanced. (1 Point)
True
False***
2. Most people in the United States use feet and miles to measure distance in their everyday lives. Why do scientists in the United States use meters to measure distance? (1 Point)
A) Meters allow scientists to be more accurate in their measurements.***
B) Science requires special measurements that are not used in everyday life.
C) All scientists use meters to measure distance to help eliminate confusion.
D) Meters are better than feet for measuring objects in motion.
3. Which of the following forces causes a feather to fall slower than a bowling ball?
A) Gravity
B) Rolling Friction
C) Sliding Friction
D) Air Resistance***
4. A small fish in the Pacific Ocean watches a shark swim by a large rock a few meters away. Which of the following is the reference point in this scenario?
A) Shark
B) Large rock***
C) Water
D) Pacific Ocean
5. Which of the following pairs of objects would have the strongest gravitational pull?
A) two tall buildings in the same city
B) two tall buildings in different cities
C) two stars very far away from each other
D) two stars very close to each other***
6. A maglev train uses powerful magnets to lift the train above the tracks as it moves forward. Such a design reduces which of the following forces?
A) Rolling friction***
B) Gravity
C) Air resistance
D) Fluid friction
7. Which of the following examples does NOT demonstrate a change in velocity?
A) An elevator slows down in order to stop at the top floor
B) A cruise ship travels west at a constant speed***
C) A soccer ball is passed across the field or
D) A train remains at a constant speed as it moves around the bend
8. Which of the following does NOT need to be measured in order to describe motion?
A) size of an object ***
B) distance the object traveled
C) velocity of the object
D) acceleration of the object
Please respond as soon as you see this. Thank you. :)
1. If the net force on an object is 0 N, the forces are considered unbalanced.
False
To determine if the forces on an object are balanced or unbalanced, we need to consider the net force acting on the object. If the net force is zero, it means that the forces are balanced, and there is no overall acceleration of the object. If the net force is not zero, it means that the forces are unbalanced, and there will be a change in the object's motion.
2. Most people in the United States use feet and miles to measure distance in their everyday lives. Why do scientists in the United States use meters to measure distance?
A) Meters allow scientists to be more accurate in their measurements.
Scientists in the United States (and around the world) use the metric system, including meters, because it provides a standardized and internationally accepted system of measurement. The metric system is based on powers of 10, which makes calculations and conversions between different units much easier. It also allows for greater accuracy and precision in scientific measurements.
3. Which of the following forces causes a feather to fall slower than a bowling ball?
D) Air Resistance
When an object falls through the air, it experiences the force of gravity pulling it downward. However, objects with a larger surface area, such as a feather, experience a greater amount of air resistance. Air resistance is a force that opposes the motion of an object through the air. The feathers are able to slow down their fall more effectively compared to a dense object like a bowling ball, which is less affected by air resistance.
4. A small fish in the Pacific Ocean watches a shark swim by a large rock a few meters away. Which of the following is the reference point in this scenario?
B) Large rock
In this scenario, the reference point is the large rock. A reference point is a location or object used to describe the position or motion of another object. When the fish is watching the shark swim by, it is using the large rock as a point of reference to determine the relative position and motion of the shark.
5. Which of the following pairs of objects would have the strongest gravitational pull?
D) two stars very close to each other
Gravitational pull is determined by the mass of the objects and the distance between them. The closer the objects and the greater their mass, the stronger the gravitational pull between them. Therefore, two stars that are very close to each other would have a stronger gravitational pull compared to any of the other options provided.
6. A maglev train uses powerful magnets to lift the train above the tracks as it moves forward. Such a design reduces which of the following forces?
A) Rolling friction
Rolling friction is the force that opposes the motion of an object as it rolls over a surface. In the case of a maglev train, the use of powerful magnets lifts the train above the tracks, reducing the contact area and minimizing rolling friction. This design allows for smoother and more efficient movement of the train.
7. Which of the following examples does NOT demonstrate a change in velocity?
B) A cruise ship travels west at a constant speed
Velocity is a vector quantity that includes both magnitude (speed) and direction. A change in velocity occurs when there is a change in either the speed or direction of motion. In the example of a cruise ship traveling west at a constant speed, the velocity remains constant because the ship maintains the same speed and direction. Therefore, there is no change in velocity.
8. Which of the following does NOT need to be measured in order to describe motion?
A) size of an object
To fully describe the motion of an object, we need to measure certain quantities. These include:
- Distance or displacement (the change in position of the object)
- Time (the duration of motion)
- Velocity (the speed and direction of motion)
- Acceleration (the rate at which velocity changes)
The size of an object, such as its physical dimensions or mass, is not directly related to motion and does not need to be measured to describe it.