Work and Energy

If you push twice as hard against a stationary brink wall, the amount of work you do

• doubles

• is cut in half

• remains constant but non-zero

• remains constant at zero

A 50 N object was lifted 2.0 m vertically and is being held there. How much work is being done in holding the box in this position?

• more than 100 J

• 100 J

• less than 100 J, but more than 0 J

• 0 J

Tags

NGSS.HS-PS2-1

NGSS.HS-PS2-4

You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes down.

• work is + on the way up and + on the way down

• work is - on the way up and - on the way down

• work - on the way up and + on the way down

• work is + on the way up and - on the way down

The area under the curve, on a force vs. position ( F vs. x ) graph, represents

• work

• kinetic energy

• power

• potential enery

If the net work done on an object is positive, then the objects's kinetic energy

• decreases

• remains the same

• increases

• is zero

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-2

If the net work on an object is zero, then the object's kinetic energy

• decreases

• remains the same

• increases

• is zero

Tags

NGSS.HS-PS2-1

The quantity 1/2kx² is

• the kinetic energy of the object

• the elastic potential energy of the object

• the work done on the object by the force

• the power supplied to the object by the force

A ball drops some distance and gains 30 J of kinetic energy. Do not ignore air resistance. How much gravitational potential energy did the ball lose?

• more than 30 J

• exactly 30 J

• less than 30 J

• cannot be determined from the given information

Tags

NGSS.HS-PS3-2

The quantity F*d/t is

• the kinetic energy of the object

• the potential energy of the object

• the work done on the object by the force

• the power supplied to the object by the force

Compared to yesterday, you did 3 times the work in one-third the time. To do so, your power output must have been-

• the same as yesterday's power output

• one-third of yesterday's output

• 3 times yesterday's output

• 9 times yesterday's power output