Question

7. A mover pushes a 1700 N piano up a 4-meter ramp. How much work is done
by the mover? Be sure to show work and label units
8. How much work is done when an engine generates 400 watts of power in 25
seconds? Show work and label units
Plz guys help me very urgent

Answer 1

Answer:

power?

the strength of someone or something

the force that is used

the work that is done

the rate at which work is done

2. Which of the following best describes the concept of work?

a force applied to an object

a force moves an object through a distance

the transformation of energy

the rate at which energy is transformed

3. What is the unit for work?

joule

joule per second

newton

watt

4. One watt equals one .

newton

newton-meter

meter per second

joule per second

5. How much power is needed to complete 150 Joules of work in 40 seconds?

3.75 (3 3/4) watts

600 watts

14 watts

6. A weightlifter holds an 800-newton barbell over his head at a height of 6 meters. How much work does the weight lifter do on the barbell?

0 J

0 W

4,800 J

4,800 W

7. A mover pushes a 1700 N piano up a 4 meter ramp. How much work is done by the mover? Be sure to show work and label units.

W=fd

W=(1700N)(4m)

W=6800 J

8. How much work is done when an engine generates 400 watts of power in 25 seconds? Show work and label units.

Power = work/time

Work = power x time

Work = 400 watts x 25 seconds

Work = 10,000 J

9. Define the work-energy theorem in your own words.

Answer should be something along the lines of: The work done on an object by all the forces acting on it equals the change in kinetic energy of that object.

10. Foster usually walks up three flights of stairs to his physics class without getting tired. However on Monday, he is late for class and decides to run up the three flights of stairs. Although he did not run for a long period of time and traveled the same distance as normal, Foster feels more tired at the top of the stairs than on the days he walks. Use the concept of power to explain why he feels more tired.

Power is the rate at which work is done or work divided by time. He traveled the same distance (three flights of stairs) and overcame the same forces (weight) in a shorter time period than normal. This required a greater output of power than on the days Foster walks up the stairs. Foster transformed the energy required to get up the stairs in a shorter time period, tiring him out at a faster rate than if he walked.

Answer 2

$\sf{7.\:\:W=F×s}$

$\sf{:\implies{W=1700N×4m}}$

$\sf{:\implies{W=6800J}}$

$\sf{\bold{\bold{———————————————}}}$

$\sf{8.\:\:∵Power=work/time}$

$\sf\therefore{Work=power×time}$

$\sf{:\implies{Work=400\:watts×25\:seconds}}$

$\sf{:\implies{Work=10,000J}}$