Work, Energy and Machines

A forklift lifts 5 boxes from the ground to a height of 2 meters (m). The boxes push down with a force of 1000 Newtons (N). How much work was done by the forklift to lift the boxes?

• 200J 
• 500J
• 2000J
• 10000J

A force of 12 N is used to lift a box 0.5 meters above a floor. What amount of work was done to lift the box?

• 6.0 N/m  
• 11.5 N
• 12.5 N 
• 24.0 N/m

How much work is done in moving the cart?  

• 20J  
• 500J 
• 1000 J
• 2000 J

Tags

NGSS.HS-PS2-1

How much power is required to lift a 2.0 kg object 5 meters in 4.50 seconds?  

• 0.45 Watts  
• 2.22 Watts
• 21.8 Watts
• 45.0 Watts 

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

The efficiency of a machine is always less than 100 percent because

• a machine cannot have an IMA greater than 1. 
• some work input is lost to friction.
• the work input is too small.
• the work output is too great.

Tags

NGSS.MS-ETS1-1

NGSS.MS-PS3-3

If you know the input distance and output distance of a machine, which of the following can you calculate?

• work
• efficiency
• actual mechanical advantage
•  ideal mechanical advantage

An inclined plane reduces the effort force by

• increasing the distance through which the force is applied.
• increasing the work.
• reducing the effort distance.
• reducing the work.

Tags

NGSS.MS-ETS1-1

The ideal mechanical advantage of a pulley system is equal to the

• distance the load has to move.
• length of the rope.
• number of rope  segments supporting the load.  
• weight of the object being lifted.

Tags

NGSS.MS-ETS1-2

Which of the following is not a type of simple machine?

• screw 
• wedge 
• lever
• handle

What does the power of a machine measure?  

• The rate of doing work.
• The strength of the machine. 
• The force the machine produces. 
• The total amount of work completed.

Tags

NGSS.MS-PS3-5