Simple Machines Test 2023

A force acting on an object does NO work if

• a machine is used to move the object

• the force is not in the same direction as the objects motion

• the force is greater that the force of friction

• the object accelerates

A machine is a device that can multiply

• force

• power

• work

• all of the above

How can a machine make work easier for you?

• by decreasing friction

• by increasing your force

• by increasing the work done by the machine

• none

Tags

NGSS.MS-ETS1-1

NGSS.MS-ETS1-2

How can you make the work output of a machine greater than the work input

• by decreasing the friction

• by increasing the input force

• by increasing the output distance

• you cannot, because friction is always present

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

• work

• actual mechanical advantage

• efficency

• Ideal mechanical advantage

If you have to apply 40 N of force on a crow bar to lift a rock that is 400N what is the mechanical advantage of the crow bar?

• 0.1

• 10

• 360

• 16,000

Tags

NGSS.MS-ETS1-1

A 120m long ski lift carries skiers from a station at the foot of a slope to another station 40m above, what is the mechanical advantage of the lift?

• 0.3

• 3

• 40

• 160

Tags

NGSS.MS-ETS1-2

Reducing friction in a machine

• decreases mechanical advantage

• decreases the work output

• increases the effeciency

• increases the ideal mechanical advantage

Tags

NGSS.MS-PS2-2

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

• machine cannot have IMA greater than 1`

• Some work input is lost to friction

• the work input is too small

• the work output is too great

A mechanical device requires 420 J of input work to do 230 J of work in lifting a crate what is the efficiency of the device?

• 0.5%

• 190%

• 55%

• 183%

Tags

NGSS.MS-PS3-5