1. If the net force on an object is O N, the forces are considered unbalanced
true
false
2. Most people in the united states use feet and miles to measure distance in their everyday lives. why do scientist in the United States use meters to measure distance?
Meters allow scientist to be more accurate in their measurements
science requires special measurements that are not used in everyday life
All scientist use meters to measure distance to help eliminate confusion
meters are better than feet for measuring objects in motion
3. Which of the following forces cause a feather to fall slower than a bowling ball?
gravity
rolling friction
sliding friction
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 a reference point in this scenario?
shark
large rock
water
pacific ocean
5. Which of the following pairs of objects would have the strongest gravitational pull?
Two tall buildings in the same city
two tall buildings in different cities
two stars very far away from each other
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?
rolling friction
gravity
air resistance
fluid friction
7. which of the following examples does not demonstrate a change in velocity
an elevator slows down in order to stop at the top floor
a cruise ship travels west at a constant speed
a soccer ball is passed across a field
a train remains at a constant speed as it moves around a bend.
8. which of the following does not need to be measured in order to describe motion?
size of the object
distance the object traveled
velocity of the object
acceleration of the object
5 is D, close stars. Gravity force between stars is huge despite distance
F = G M2 M2 / d^2
between A and B it would be A because same mass but closer (smaller d^2)
7 is B Train around bend is change in DIRECTION. velocity is vector, speed and DIRECTION
8 is A, size is not motion
sometimes twin stars hold each other in orbit. Imagine the huge gravitational force !
my answers:
1.A
2.C
3.D
4.B
5.B
6.A
7.DC
8.
7.D
8.C
Hey, I already passed the course. You try to answer the questions and one of us might check and figure out what you are missing. We are not here to take the course for you.
Oh ok I will check
1. False. If the net force on an object is zero, the forces are considered balanced, not unbalanced.
To determine if forces are balanced or unbalanced, you need to calculate the net force acting on the object. The net force is the vector sum of all the forces acting on the object. If the net force is zero, the forces are balanced and the object will remain at rest or continue moving at a constant velocity. If the net force is non-zero, the forces are unbalanced and the object will experience acceleration in the direction of the net force.
2. Meters allow scientists to be more accurate in their measurements.
Scientists in the United States, like scientists around the world, use the metric system, which includes the meter as the unit for measuring distance. The metric system is based on powers of ten, which makes it easier to convert between units and make precise measurements. The use of meters allows scientists to have a standardized and consistent system for measuring distance, which is crucial in scientific experiments and calculations.
3. Air resistance.
In this scenario, the force that causes the feather to fall slower than a bowling ball is air resistance. Air resistance is a force that opposes the motion of objects through air. It becomes more significant at higher speeds and affects objects with larger surface areas, like feathers, more than objects with smaller surface areas, like bowling balls. The air resistance acts in the opposite direction to the motion of the falling object, reducing its acceleration and causing it to fall slower.
4. Large rock.
In this scenario, the large rock is a reference point. A reference point is a location or object used to describe the motion of another object. It provides a frame of reference against which motion can be observed and measured. The small fish is observing the shark's motion relative to the large rock, which helps in determining the distance between them or the speed of the shark.
5. Two stars very close to each other.
In this scenario, two stars very close to each other would have the strongest gravitational pull. Gravity is a force that attracts two objects towards each other. The strength of the gravitational pull depends on the mass of the objects and the distance between them. When two objects have a larger mass and are closer together, the gravitational force between them is stronger.
6. Rolling friction.
In this scenario, the design of the maglev train using powerful magnets helps reduce rolling friction. Rolling friction is the force that opposes the motion of an object rolling on a surface. By using powerful magnets to lift the train above the tracks, the train can move forward with minimal contact and friction with the tracks. This reduces the rolling friction and allows for smoother and more efficient movement of the train.
7. A soccer ball is passed across a field.
In this scenario, passing a soccer ball across a field does not demonstrate a change in velocity. Velocity is a vector quantity that includes both speed and direction. When an object undergoes a change in velocity, it means there is a change in either its speed or direction or both. In the case of passing a soccer ball across a field, the ball may change its speed as it is kicked, but its overall direction remains consistent. Therefore, it does not demonstrate a change in velocity.
8. Size of the object.
In order to describe the motion of an object, the size of the object does not need to be measured. Motion is concerned with the object's change in position over time, its velocity, and its acceleration. The size of the object does not directly affect these motion parameters. However, the distance the object traveled, its velocity, and its acceleration are all important measurements to describe the object's motion accurately.