Work and Machines

Which of the following is work according to the scientific definition?

• pushing a box across the floor
• standing still while holding something heavy
• walking with a backpack on
• all of these are considered "work"

Work only occurs when the direction of motion and direction of force are in the same direction.

• TRUE
• FALSE

Work can occur without motion.

• TRUE
• FALSE

Using 10 N of force to move a box 2 m,
= how much work?

• 0 (zero) J
• 20 J
• 12 J
• 8 J

Tags

NGSS.MS-PS3-5

Device that makes work easier by changing the size or direction of the force  (or both) is called a

• simple machine
• spring scale
• newton
• pulley

What unit is used to measure work?

• Joule
• Meter
• Newton
• Gram

Tags

NGSS.MS-PS3-5

Simple machines make work easier by 

• increasing the energy needed to do the work, while reducing friction.
• changing the size or direction of the force, or both
• reducing work
• simple machines do all of these

Tags

NGSS.MS-ETS1-1

How does a ramp (inclined plane) make work easier?

• changing the direction of both the effort (input) force and the output force (load).
• decreasing the size of the effort force needed, by increasing the distance.

How does a single fixed pulley make work easier?

• It changes the direction of the force.  It is easier to pull downward.
• It increases the size of the force required by decreasing the distance.

Which pulley makes work easiest?

• 1
• 2
• 3
• they are all the same