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)
• 2,000 joules
• 1,600 joules
• 400 joules
• 100 joules
The work done by a person is calculated using the formula:
Work = Force * Distance
Given:
Force = 400 newtons
Distance pushed = 4 meters
Distance slid after pushing stopped = 1 meter
Work done while pushing = Force * Distance
= 400 newtons * 4 meters
= 1600 joules
Work done after pushing stopped = Force * Distance
= 400 newtons * 1 meter
= 400 joules
Total work done = Work done while pushing + Work done after pushing stopped
= 1600 joules + 400 joules
= 2000 joules
Therefore, the correct answer is:
• 2,000 joules
In this pulley system, the pulleys will ? the mechanical force required to lift the block and will change the ?.
(1 point)
• decrease; weight of the block
• decrease; direction of the force
• increase; weight of the block
• increase; direction of the force
• decrease; weight of the block
In a pulley system, the mechanical advantage increases as the number of pulleys increase, making it easier to lift an object. The pulleys will decrease the mechanical force required to lift the block by distributing the force over multiple ropes and pulleys. This, in effect, decreases the weight of the block that needs to be lifted by the person.
Which list correctly orders effort (E), fulcrum (F), and load (L) for each lever class? (1 point)
• 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 = 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 = 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 = 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)
How do simple machines make work easier? (1 point)
• They reduce the amount of force needed to move an object to do the same amount of work.
• 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 increase the distance over which a force is needed, doing more work with less force.
• They decrease the distance needed between a person and an object, allowing the person to apply more force and do more work.
• They reduce the amount of force needed to move an object to do the same amount of work.
A person applies 98 Newtons of force to a 20 kilogram box. They apply the force to the box over a 4-meter ramp, raising the box 2 meters from the ground. How much work is done? (1 point)
• 392 Joules
• 80 Joules
• 40 Joules
• 194 Joules
The work done by a person is calculated using the formula:
Work = Force * Distance
Given:
Force = 98 newtons
Distance pushed = 4 meters
Height lifted = 2 meters
Work done = Force * Distance
= 98 newtons * 4 meters
= 392 joules
Therefore, the correct answer is:
• 392 Joules
A person is lifting a heavy box using a lever. What is the purpose of the lever in this situation? (1 point)
• to reduce the energy 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 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