U9 Work and Simple Machine Summative Review

Simple machines make work easier by increasing

• the distance over which the work is done
• The time required to do the work
• the force needed to do work
• the acceleration of a large object

Which of the following does a simple machine do?

• allows the user to apply less force over a longer distance
• change the direction of the applied force
• reduce the amount of force needed to do work
• all of the above

Tags

NGSS.MS-PS2-2

Choose all correct answers. What are the 6 simple machines that make work easier?

• block, inclined plane, lever, metal chain, pulley, screw
• inclined plane, lever, metal chain, pulley, screw
• lever, inclined plane, pulley, screw, metal chain, block
• metal chain, wedge, wheel & axle, lever, block, pulley
• pulley, screw, inclined plane, wheel & axle, wedge, lever

The force that interferes with useful work done by a machine due to heat between surfaces that are touching.

• efficiency
• fricition
• mechanical advantage
• effort arm

The amount of useful work obtained by using a machine.

• work input
• work output
• resistance force
• friction

Tags

NGSS.MS-PS3-5

Which of the following is NOT a case of work being done on an object?

• A worker pushes a box up a ramp into a truck
• A woman holds a heavy box in her arms
• A father lifts a baby out of a crib
• A baseball is thrown into the outfield

Power is

• how strong someone or something is
• how much force is being used
• how much work is being done
• how fast work is being done

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Use the formula Work=Force X Distance: Which of the following is doing more work on an object?

• lifting a 120 N box 1 m up off the floor
• lifting a 160 N box 1 m up off the floor
• lifting a 70 N box 2 m up off the floor
• lifting a 100 N box 1.5 m up off the floor

Use the formula Power=Work/time: If you do 500J of work in 2 sec, your power is?

• 10W
• 45W
• 52W
• 250W

How does a pulley make work easier?

• uses a rope
• you pull up on the rope
• you pull down on the rope to work with gravity
• makes the distance for the load shorter from the ground to the truck

Tags

NGSS.MS-ETS1-1