Question

2. If you exert a force of 10.0 N to lift a box a distance of 0.9 m, how much work have you done? (1 point)
0.1 J
9.0 J
10.9 J
90.0 J
3. The power of a machine measures (1 point)
its rate of doing work.
its strength.
the force it produces.
the work it does.
4. If you exert a force of 700 N to walk 6 m up a flight of stairs in 6 s, how much power do you use? (1 point)
19 W
25,200 W
700 W
4,200 W
5. A 750-W motor might also be rated as a (1 point)
0.5-horsepower motor.
1-horsepower motor.
2-horsepower motor.
10-horsepower motor.

Answer 1

what class is this ? i think i took this

Answer 2

2. Work equals force time distance so the answer is nine joules.\[W=Fd=10N0.9m=9J\]3. Power equals the rate of work so the answer is "its rate of doing work."
4. Power equals the work divided by time. The answer is sevenhundred watts.\[P=\frac{ W }{ t }=\frac{ Fd }{ t }=\frac{ 700N6m }{ 6s }=700W\]5. One horse power equals sevenhundred fifty watts so the answer is one horse power.\[750W=750W\frac{ 1hp }{ 750W }=1hp\]

Answer 3

The problem with the answer above is that m is not 10, 10 is the force needed to raise it up. Actually m would be 1 kg (asuming 10 is the gravitational acceleration not 9.8) since the force needed (10N) must be equal to mg to raise it at constant speed. So your answer should be:\[W=PE=mgh=1kg10\frac{ m }{ s ^{2} }0.9m\]

Answer 4

whats number 2s answer?

Answer 5

9