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?
• 100 joules
• 2,000 joules
• 1,600 joules
• 400 joules
1. 1,600 joules
2. decrease; direction of the force
3. 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)
4. They reduce the amount of force needed to move an object to do the same amount of work.
5. 392 Joules
6. to reduce the force needed to lift the box and change the direction of the force
7. It is the point where the bar touches the smaller rock.
8. a car that traveled 80 kilometers on 5.0 liters of gas
9. machine C
10. It changes the direction of the lifting force to work with gravity.
11. Use a stiffer lever to reduce energy lost bending the lever.
12. 60%
<3
work = force * distance = 400*4 = 1600 J
Friction did an equal amount of work in stopping the box.
@buddy#2761
TYSM!! <33
work= force*distance=400*4= 1.6kjoules
@buddy#2761
Tysm!! I got 100%%%
All those answers are correct!!!
OMG TYSM @buddy#2761
YOUR THE BEST!
for 6, the answer is “to reduce the force needed to lift the box and change the direction of the force”!!
OMG thank you i was going to fail that thank you!!!!!!!!!!
"hmm." thats exacty what Buddy put-- but yeah 12/12 tysmm <33
For Connections Academy
Please only use this to check your answers.
1. 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?
A. 400 joules
B. 2,000 joules
C. 1,600 joules***
D. 100 joules
2. In this pulley system, the pulleys will _____ the mechanical force required to lift the block and will change the _____.
A. increase; direction of the force
B. decrease; direction of the force***
C. increase; weight of the block
D. decrease; weight of the block
3. Which list correctly orders effort (E), fulcrum (F), and load (L) for each lever class?
class 1 = L,F,E (or E,F,L)***
A. class 2 = F,L,E (or E,L,F)
class 3 = F,E,L (or L,E,F)
class 1 = F,E,L (or L,E,F)
B. 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)
C. class 2 = F,E,L (or L,E,F)
class 3 = L,E,F (or F,E,L)
class 1 = F,E,L (or L,E,F)
D. class 2 = F,L,E (or E,L,F)
class 3 = L,F,E (or E,F,L)
4. How do simple machines make work easier?
A. They decrease the distance needed between a person and an object, allowing the person to apply more force and do more work.
B. They increase the distance over which a force is needed, doing more work with less force.
C. They reduce the amount of force needed to move an object to do the same amount of work.***
D. They magnify the force being applied, thereby decreasing the work they can do with no extra energy exerted by the person using the machine.
5. 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?
A. 392 joules***
B. 40 joules
C. 80 joules
D. 196 joules
6. A person is lifting a heavy box using a lever. What is the purpose of the lever in this situation?
A. to reduce the force needed to lift the box and change the direction of the force***
B. to reduce the energy needed to lift the box and change the direction of the force
C. to reduce the energy needed to lift the box while keeping the direction of the force the same
D. to reduce the force needed to lift the box while keeping the direction of the force the same
Use the image of a person lifting a boulder with a lever to answer the question.
7. Where is the fulcrum in this situation?
A. It is the point where the bar touches the boulder.
B. It is the point where the person’s hands push down on the bar.
C. It is the point where the bar touches the smaller rock.***
D. It is the point where the boulder touches the ground.
8. In which situation did the car achieve the greatest efficiency? (Assume the cars all have the same mass.)
A. a car that traveled 80 kilometers on 5.0 liters of gas***
B. a car that traveled 70 kilometers on 5.0 liters of gas
C. a car that traveled 90 kilometers on 6.0 liters of gas
D. a car that traveled 50 kilometers on 4.0 liters of gas
9. 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?
A. machine A
B. machine C***
C. machine D
D. machine B
10. How does a pulley make work easier when it is used to lift an object?
A. It increases the amount of work produced to lift the object.
B. It decreases the distance over which the force must be applied to lift the object.
C. It changes the direction of the lifting force to work with gravity.***
D. It reduces the weight of the object being lifted.
11. A certain lever system is only 30% efficient. What could make it more efficient?
A. Have more than one person help to lift the lever.
B. Use a stiffer lever to reduce energy lost bending the lever.***
C. Use it with a lighter load to make it easier.
D. Use it with a lighter load to make it easier.
12. What is the efficiency of a ramp if 2,000 joules of energy results in 1,200 joules of work?
A. 32%
B. 80%
C. 24%
D. 60%***