i need help please and fast.
How do simple machines make work easier?(1 point)
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.
In which situation did the car achieve the greatest efficiency? (Assume the cars all have the same mass.)(1 point)
A.a car that traveled 70 kilometers on 5.0 liters of gas
B.a car that traveled 90 kilometers on 6.0 liters of gas
C.a car that traveled 80 kilometers on 5.0 liters of gas
D.a car that traveled 50 kilometers on 4.0 liters of gas
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?
machine A
machine B
machine C
machine D
What is the efficiency of a ramp if 2,000 joules of energy results in 1,200 joules of work?(1 point)
24%
32%
60%
80%
6 answers