A spring scale shows a net force of 0.8 N acting on a 1.5-kg mass. What happens to the acceleration of the object if the net force is decreased to 0.2 N?(1 point)
Responses
The acceleration increases to four times its original value, or about 2.13 m/s2.
The acceleration increases to four times its original value, or about 2.13 m/s 2 .
The acceleration decreases to a quarter of its original value, or about 2.13 m/s2.
The acceleration decreases to a quarter of its original value, or about 2.13 m/s 2 .
The acceleration increases to four times its original value, or about 0.13 m/s2.
The acceleration increases to four times its original value, or about 0.13 m/s 2 .
The acceleration decreases to a quarter of its original value, or about 0.13 m/s2.
The acceleration decreases to a quarter of its original value, or about 0.13 m/s2.
A spring scale shows a net force of 0.8 N acting on a 1.5-kg mass. What happens to the acceleration of the object if the net force is decreased to 0.2 N?(1 point)
Responses
The acceleration increases to four times its original value, or about 2.13 m/s2.
The acceleration increases to four times its original value, or about 2.13 m/s 2 .
The acceleration decreases to a quarter of its original value, or about 2.13 m/s2.
The acceleration decreases to a quarter of its original value, or about 2.13 m/s 2 .
The acceleration increases to four times its original value, or about 0.13 m/s2.
The acceleration increases to four times its original value, or about 0.13 m/s 2 .
The acceleration decreases to a quarter of its original value, or about 0.13 m/s2.
The acceleration decreases to a quarter of its original value, or about 0.13 m/s2.
Use the graph of velocity vs. time for an object to answer the question.
A line graph that displays the change in velocity over time and is broken up into 3 segments. At zero seconds, the velocity is zero meters per second. At 60 seconds, the velocity is 8 meters per second. The time difference between zero and 60 seconds represents the first segment. At 150 seconds, the velocity is 14 meters per second. The time difference between 60 and 150 seconds represents the second segment. At 240 seconds, the velocity is 29 meters per second. The time difference between 150 and 240 represents the third segment.
Which statement fairly compares segment 2 and segment 3?
(1 point)
Responses
Segments 2 and 3 have different periods of time and the force during segment 2 is different than the force during segment 3.
Segments 2 and 3 have different periods of time and the force during segment 2 is different than the force during segment 3.
Segments 2 and 3 have equal periods of time but the force during segment 2 is different than the force during segment 3.
Segments 2 and 3 have equal periods of time but the force during segment 2 is different than the force during segment 3.
Segments 2 and 3 have equal periods of time and the force acting in each segment is the same during each period of time.
Segments 2 and 3 have equal periods of time and the force acting in each segment is the same during each period of time.
Segments 2 and 3 have different periods of time, but the force acting in each segment is the same during each period of time.
Segments 2 and 3 have different periods of time, but the force acting in each segment is the same during each period of time.
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Segments 2 and 3 have different periods of time, but the force acting in each segment is the same during each period of time.
Use the graph to answer the question.
A velocity versus time line graph shows three lines. The vertical axis is labeled, velocity, and the horizontal axis is labeled, time. Line A moves to the right from a point on the vertical axis above the origin parallel to the horizontal axis. Line B slopes upward from the origin to the upper right corner. Line C moves to the right from a point on the vertical axis below the origin parallel to the horizontal axis.
Which quantity or quantities is/are increasing for the object represented by Line B?
(1 point)
Responses
velocity and position
velocity and position
velocity, position, and acceleration
velocity, position, and acceleration
velocity only
velocity only
velocity and acceleration
velocity and acceleration
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velocity and position
The same type of engine is placed in two different airplanes. The first airplane is twice as heavy as the second airplane. Which statement is correct about the mass of the airplane and its acceleration, assuming a constant net force?(1 point)
Responses
Decreasing the mass of the airplane will result in the airplane accelerating more.
Decreasing the mass of the airplane will result in the airplane accelerating more.
Increasing the acceleration of the airplane causes the engine to provide less force.
Increasing the acceleration of the airplane causes the engine to provide less force.
Increasing the acceleration of the airplane causes the engine to provide more force.
Increasing the acceleration of the airplane causes the engine to provide more force.
Decreasing the mass of the airplane will result in the airplane accelerating less.
Decreasing the mass of the airplane will result in the airplane accelerating more.
The harder a gas pedal in a car is pressed, the faster the car’s velocity increases. Which phrase best describes the relationship between how hard the gas pedal is pressed and the acceleration of the car?(1 point)
Responses
There is a negative correlation but no causation.
There is a negative correlation but no causation.
There is a positive correlation but no causation.
There is a positive correlation but no causation.
There is both a negative correlation and causation.
There is both a negative correlation and causation.
There is both a positive correlation and causation.
There is both a positive correlation and causation.
A helicopter is accelerating up into the air while it is also accelerating due north. Which statement about the forces acting on the helicopter is true?(1 point)
Responses
The drag on the helicopter is directed downward and to the south.
The drag on the helicopter is directed downward and to the south.
The drag on the helicopter is directed downward and to the north.
The drag on the helicopter is directed downward and to the north.
The drag on the helicopter is directed upward and to the north.
The drag on the helicopter is directed upward and to the north.
The drag on the helicopter is directed upward and to the south.
The drag on the helicopter is directed downward and to the south.
Which state of equilibrium is a person in while running on a treadmill?(1 point)
Responses
stable equilibrium
stable equilibrium
static equilibrium
static equilibrium
neutral equilibrium
neutral equilibrium
dynamic equilibrium
dynamic equilibrium
Two galaxies on opposite ends of the universe are moving away from the Earth. Each has a velocity of 200,000 km/s relative to the Earth. How fast would an observer in one of those galaxies see the other galaxy moving away? (1 point)
Responses
between 200,000 and 300,000 km/s
between 200,000 and 300,000 km/s
400,000 km/s
400,000 km/s
200,000 km/s
200,000 km/s
between 300,000 and 400,000 km/s
between 200,000 and 300,000 km/s
Use the story and the position vs. time graph to complete the activity.
An elevator in a hotel starts at ground level. It rapidly moves up to the third floor, where it stops to unload passengers. The elevator then descends to the basement at a slower speed than before.
A line graph shows the motion of an elevator as it goes up and down. The vertical axis lists various floors of the building. The horizontal axis shows time. A line sloping upward from the ground floor to the third floor is labeled, A. A line parallel to the horizontal axis at the third floor is labeled, B. A line sloping downward from the third floor to the basement is labeled, C.
In 1–2 sentences, identify whether or not the graph correctly represents the story. Explain your answer.
(2 points)
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Short Answer Rubric (2 points)
Points Awarded Criteria
2
The answer is very clear.
The answer is fully supported by details.
There may be a few errors in grammar, usage, or mechanics. Errors do not interfere with meaning.
1
The answer is somewhat clear.
Details are weak or not related.
There are some errors in grammar, usage, and mechanics. Errors interfere with meaning.
0 The question is not answered.
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Yes, the graph correctly represents the story. The upward slope of line A represents the elevator's ascent to the third floor, line B, which is parallel to the time axis, shows the elevator stopped at the third floor, and the downward slope of line C represents the elevator's slower descent to the basement.
A student holds a water balloon outside of an open window and lets go. The window is 10 meters above the ground, and the balloon is falling under the acceleration of gravity, which is 9.8 m/s2. There are two equations that can be used to describe its motion over time:
x=x0+v0t+12at2
x
=
x
0
+
v
0
t
+
1
2
a
t
2
v=v0+at
v
=
v
0
+
a
t
Would the balloon hit the ground before or after 1.0 s of falling? Which equation did you use to decide, and what comparison did you make to determine that it would or would not hit the ground by then?
Use 3–5 sentences to explain your reasoning.
(4 points)
The balloon would hit the ground after 1.0 s of falling. This can be determined by using the first equation (x = x0 + v0*t + 0.5*a*t^2), where x0 is the initial position (10m), v0 is the initial velocity (0, as the balloon is simply dropped), a is the acceleration due to gravity (-9.8 m/s^2) and t is time. By substituting these values into the equation, after 1.0 s, the balloon would have fallen approximately 4.9 m, which is less than the total 10 m it needs to fall to hit the ground. Therefore, it will take more than 1.0 seconds for the balloon to hit the ground.
Many competitive swimmers practice in loose-fitting, baggy swimsuits called drag suits. In 1–2 sentences, explain how, in terms of the forces acting on a swimmer, wearing a drag suit differs from wearing a tight-fitting racing suit, and why practicing in a drag suit can make a swimmer stronger.(2 points)
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Short Answer Rubric (2 points)