UCONN Physics
Power, HP Worksheet
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Users Guide
Use this to guide you through each question, remember to always show your work NEATLY, label units and circle final answers.
1. Done in Class:
Solve for acceleration (a) and average velocity (V)
Set up equation: P = W/t = ( F • D)/ t = F • velocity = ma • velocity
2. Done in Class:
Set up equation: P = W/t = (F • D) / t = [Use force (weight of barbell) • Vertical distance] / time
3.
1200 M
Weight = 60 kg x 9.8 m/s 2 = 588 N
Power = 500 Watts @ 100%
Power = 500 Watts • 0.10 = 50 Watts @ 10 %
Solve this twice, once for each power. Using P = W/t
Be mindful of units as Work = nm and watts = J/s
4. Use formula P = work/time = F • D / t = F • velocity
Find power at 100% then solve for P @ 40%
0.40P = = F • D / t = F • velocity
5. Light Bulb = 100 Watts or J/s
2000 Hours , convert to seconds. Use Formula Energy (J) = Power (W) • time (s)
Convert watts into Kilowatts by dividing by 1000. Then multiply by time in hours.
6. If the barge is moving at2 m/s and increases to 6 m/s. The Power is proportional to velocity squared, then if
If the velocity is tripled and force (power) is related to this squared, then tripled squared = 9. Thus the force
will increase by a factor of 9 or 9 fold.
7. Convert 2 HP to watts. 1 HP = 745.7 Watts there 2 HP = 1491.4 Watts
Set this in for P in the equation P = (F•D)/time solve for force, convert to mass with F = mg.
8. Use the fact that each 100 watt bulb is written. 100 Watts/bulb. Use dimensional analysis to convert
total power into total number of lights.
1 Megawatt = 1 million Watts = 1 x 10 6 Watts therefore 10 Megawatt’s is 10x as much. Convert this into
Kilowatts. To find KWH, multiply Kilowatts (kw) times hours. Then multiply this by $0.10/KWH.