Force and Work Unit Test
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Question
A person pushes a box. He applies a force of 400 newtons, and he pushes the box for a distance of 4 meters. After he stops pushing, the box slides forward another meter. How much work was done by the person?(1 point)
Responses
100 joules
100 joules
2,000 joules
2,000 joules
1,600 joules
1,600 joules
400 joules
400 joules
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Yes, I apologize for the mistake earlier. The correct answer is:
class 1 = F, E, L (or L, E, F)
class 2 = L, F, E (or E, F, L)
class 3 = E, F, L (or L, F, E)
So, the correct answer is: class 1 = F, E, L (or L, E, F), class 2 = L, F, E (or E, F, L), class 3 = E, F, L (or L, F, E).
The correct answer is 1,600 joules. Work is calculated using the formula W = Fd, where W is work done, F is the applied force in newtons, and d is the distance moved in meters. In this case, W = 400 N x 4 m = 1,600 J. The additional meter the box slides does not affect the work done by the person, as they are not applying a force during that distance.
Force and Work Unit Test
2 of 122 of 12 Items
Question
Use the diagram of the pulley system to complete the statement.
An illustration shows a system of two pulleys lifting a block.
In this pulley system, the pulleys will _____ the mechanical force required to lift the block and will change the _____.
(1 point)
Responses
increase; direction of the force
increase; direction of the force
increase; weight of the block
increase; weight of the block
decrease; weight of the block
decrease; weight of the block
decrease; direction of the force
decrease; direction of the force
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The correct answer is decrease; direction of the force. Pulleys are simple machines that can be used to change the direction of a force and/or decrease the amount of force required to lift an object. In this pulley system, the pulleys will decrease the mechanical force required to lift the block and will change the direction of the force. By using two pulleys, the force required to lift the block is cut in half, making it easier to lift.
Which list correctly orders effort (E), fulcrum (F), and load (L) for each lever class?(1 point)
Responses
class 1 = F, E, L (or L, E, F)
class 2 = L, F, E (or E, F, L)
class 3 = F, L, E (or E, L, F)
class 1 = F, E, L (or L, E, F), , class 2 = L, F, E (or E, F, L), , class 3 = F, L, E (or E, L, F)
class 1 = F, L, E (or E, L, F)
class 2 = F, E, L (or L, E, F)
class 3 = L, F, E (or E, F, L)
class 1 = F, L, E (or E, L, F), , class 2 = F, E, L (or L, E, F), , class 3 = L, F, E (or E, F, L)
class 1 = F, E, L (or L, E, F)
class 2 = F, L, E (or E, L, F)
class 3 = L, F, E (or E, F, L)
class 1 = F, E, L (or L, E, F), , class 2 = F, L, E (or E, L, F), , class 3 = L, F, E (or E, F, L)
class 1 = L, F, E (or E, F, L)
class 2 = F, L, E (or E, L, F)
class 3 = F, E, L (or L, E, F)
class 1 = L, F, E (or E, F, L), , class 2 = F, L, E (or E, L, F), , class 3 = F, E, L (or L, E, F)
can u pls answer my question?
thank you
You're welcome! Let me know if you have any other questions.
How do simple machines make work easier?(1 point)
Responses
They decrease the distance needed between a person and an object, allowing the person to apply more force and do more work.
They decrease the distance needed between a person and an object, allowing the person to apply more force and do more work.
They increase the distance over which a force is needed, doing more work with less force.
They increase the distance over which a force is needed, doing more work with less force.
They magnify the force being applied, thereby decreasing the work they can do with no extra energy exerted by the person using the machine.
They magnify the force being applied, thereby decreasing the work they can do with no extra energy exerted by the person using the machine.
They reduce the amount of force needed to move an object to do the same amount of work.
The correct answer is: They reduce the amount of force needed to move an object to do the same amount of work. Simple machines help to accomplish work in a more efficient way by reducing the amount of force needed to move an object. For example, levers or pulleys can decrease the amount of force required to lift a heavy object, while inclined planes or wedges can reduce the force needed to move an object over a distance. This means less work is required to accomplish the same task.
A person using a lever applies 98 Newtons to lift a 20-kilogram box. They apply the force over a distance of 4 meters to lift the box a distance of 2 meters. How much work is done?(1 point)
Responses
196 Joules
196 Joules
40 Joules
40 Joules
392 Joules
392 Joules
80 Joules
80 Joules
The correct answer is 392 Joules. Work is calculated using the formula W = Fd, where W is work done, F is the applied force in Newtons, and d is the distance moved in meters. In this case, the force applied is 98 N and the distance moved is 2 meters. However, to find the work done by the person, we need to use the force and distance over which they applied the force, which is 4 meters. So, W = 98 N x 4 m = 392 J.
A person is lifting a heavy box using a lever. What is the purpose of the lever in this situation?(1 point)
Responses
to reduce the force needed to lift the box while keeping the direction of the force the same
to reduce the force needed to lift the box while keeping the direction of the force the same
to reduce the energy needed to lift the box while keeping the direction of the force the same
to reduce the energy needed to lift the box while keeping the direction of the force the same
to reduce the force needed to lift the box and change the direction of the force
to reduce the force needed to lift the box and change the direction of the force
to reduce the energy needed to lift the box and change the direction of the force
to reduce the energy needed to lift the box and change the direction of the force
The correct answer is: to reduce the force needed to lift the box while keeping the direction of the force the same. The lever's purpose is to allow the person to apply less force over a greater distance to lift the load. This makes it easier for the person to lift the load that they wouldn't be able to lift without the lever. However, the direction of the force does not change through the lever; it only amplifies the applied force while keeping the force pushing in the same direction.
Force and Work Unit Test
8 of 128 of 12 Items
Question
In which situation did the car achieve the greatest efficiency? (Assume the cars all have the same mass.)(1 point)
Responses
a car that traveled 50 kilometers on 4.0 liters of gas
a car that traveled 50 kilometers on 4.0 liters of gas
a car that traveled 80 kilometers on 5.0 liters of gas
a car that traveled 80 kilometers on 5.0 liters of gas
a car that traveled 70 kilometers on 5.0 liters of gas
a car that traveled 70 kilometers on 5.0 liters of gas
a car that traveled 90 kilometers on 6.0 liters of gas
The efficiency of a car is calculated as the distance traveled divided by the amount of fuel consumed. Therefore, the car with the greatest efficiency would be the one that traveled the farthest distance with the least amount of fuel consumed. So, the answer is the car that traveled 80 kilometers on 5.0 liters of gas.
Use the table to answer the question.
Machine Output Work (J) Input Work (J)
A 750 1,500
B 1,000 4,000
C 450 600
D 3,000 5,000
Which machine has the highest efficiency?
(1 point)
Responses
machine D
machine D
machine A
machine A
machine B
machine B
machine C