Average power needed to lift an object

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SUMMARY

The average power needed to lift a 115kg weight to a height of 1.95m in 1.25 seconds is calculated to be approximately 1,982.01 Watts. The initial attempt at calculating acceleration was incorrect, as the average velocity was mistakenly used instead of applying the kinematic equation. The correct approach involves using the formula for gravitational potential energy (mgh) divided by time to determine power, which simplifies the calculation significantly.

PREREQUISITES
  • Understanding of basic physics concepts such as force, work, and power
  • Familiarity with kinematic equations, specifically s = ut + 0.5at²
  • Knowledge of gravitational force calculations (mg)
  • Ability to perform unit conversions and basic algebraic manipulations
NEXT STEPS
  • Study the kinematic equations in detail, focusing on their applications in physics problems
  • Learn about gravitational potential energy and its implications in power calculations
  • Explore the concept of constant velocity lifts and their impact on power output
  • Practice solving similar physics problems involving work and power calculations
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators looking for examples of power calculations in real-world scenarios.

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Homework Statement



A weightlifter raises a 115kg weight from the ground to a height of 1.95m in 1.25 seconds. What is the average power of this maneuver.

Homework Equations



m = 115kg
Change in Y = 1.95m
time = 1.25 seconds


The Attempt at a Solution



V = 1.95/1.25 = 1.56 m/s
a = 1.56/1.25 = 1.248 m/s/s
mg = (115)(-9.8) = -1127 N

Net Force Of Fy = (115)(1.248)
Net Fy = 143.52
Force of maneuver:
143.52 = -1127 + x
Force of maneuver = 1270.52

Work = 1270.52 * 1.95
Work = 2477.514

P = 2477.514 / 1.25 = 1,982.0112

Help?
 
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Your acceleration is wrong, the 'V' you worked out was the average velocity, you can work out the acceleration using s = ut +0.5at^2.

Alternatively assume the lift is of constant velocity and say:

mgh / time = power
 

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