An athlete can run 9 kilometers in 1 hour. If the athlete runs at that same average speed for 30 minutes, how far will the athlete travel?
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1 point
A 18 kilometers
B 9 kilometers
C 4.5 kilometers
D It travels right at an increasing speed.
The athlete can run 9 kilometers in 1 hour. Since 1 hour is equal to 60 minutes, we can divide 9 kilometers by 60 minutes to find the speed of the athlete in kilometers per minute.
9 kilometers / 60 minutes = 0.15 kilometers per minute
Since the athlete is running at the same average speed for 30 minutes, we can multiply the speed (0.15 kilometers per minute) by the time (30 minutes) to find the distance traveled.
0.15 kilometers per minute * 30 minutes = 4.5 kilometers
Therefore, the athlete will travel 4.5 kilometers in 30 minutes. The answer is C) 4.5 kilometers.
A student pushed a large rubber ball on a flat, frictionless surface. The ball rolled at a speed of 1 meter per second. Which statement best describes the motion of the ball when the student stopped pushing the ball?
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1 point
A The ball did not move
B The ball accelerated.
C The ball changed direction.
D The ball continued to move in the same direction.
The answer is D) The ball continued to move in the same direction.
Since there is no friction on the surface and the ball is rolling at a constant speed of 1 meter per second, there are no external forces acting on the ball to stop it or change its direction. Therefore, when the student stops pushing the ball, it will continue to move in the same direction with the same speed.
The three vehicles shown below are all traveling at a speed of 15 m/s, but only the pickup truck has a changing velocity. The pickup truck is accelerating because the pickup truck -
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1 point
Captionless Image
A can accelerate faster than the other two vehicles
B is traveling in the opposite direction from the other two vehicles
C is traveling on a curve in the road
D needs a large amount of force to move
The answer is C) is traveling on a curve in the road.
When a vehicle is traveling on a curved path, even if it is at a constant speed, its velocity is constantly changing. This is because velocity is a vector quantity that includes both speed and direction. In this case, the pickup truck is the only vehicle traveling on a curve, so its velocity is changing, and it is therefore accelerating. The other two vehicles are moving in a straight line, so their velocities (directions) are not changing, and they are not accelerating.
The diagrams show forces acting on a toy car as it moves to the right. Which diagram shows the toy car that will most likely accelerate to the right based on these conditions?
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1 point
Captionless Image
F
G
H
J
Without the ability to see the diagrams, it is not possible to determine which diagram shows the toy car that will most likely accelerate to the right. Please provide more information or describe the diagrams in order to assist further.
Kara pushes her big brother on a swing at the playground. After he gets off the swing, her little brother gets on. Kara finds that it is easier to push her little brother than it was to push her big brother. What is the MOST LIKELY reason for this?
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1 point
A A smaller mass always moves faster than a larger mass.
B A smaller mass always moves slower than a larger mass.
C Less force is needed to move a larger mass the same distance.
D More force is needed to move a larger mass the same distance.
The MOST LIKELY reason for Kara finding it easier to push her little brother than her big brother is because of option C) Less force is needed to move a larger mass the same distance.
According to Newton's second law of motion, the force exerted on an object is equal to the mass of the object multiplied by its acceleration. When comparing two objects with the same acceleration, the object with a larger mass will require a greater force to move.
In this case, Kara's big brother has a larger mass compared to her little brother. Therefore, to move him on the swing, Kara needs to exert more force. On the other hand, her little brother has a smaller mass, so less force is needed to move him on the swing, making it easier for Kara.
Which situation is an example of Newton’s third law of motion?
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1 point
A ball in a vacuum container moves in a straight line at a constant velocity.
A ball in a vacuum container accelerates when kicked with a great amount of force.
A person riding in a forward-moving car continues to move forward when the car stops suddenly.
A person in a canoe moves the paddle backward in the water, and the canoe moves forward in the water.