Understanding Power Calculation: 1.5MW vs 1.47MW Explained

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SUMMARY

The discussion focuses on the calculation of power in the context of a train's movement, specifically comparing 1.5 Mega Watts (MW) to 1.47 MW. The calculation presented is based on the formula power = force times velocity, resulting in 1.5 MW when using a force of 30,000 Newtons and a velocity of 50 m/s. The discrepancy arises from the subtraction of 30 kW from 1.5 MW, leading to the conclusion of 1.47 MW. The discussion also touches on the relationship between power and gravitational force, emphasizing the complexities involved in calculating power in dynamic systems.

PREREQUISITES
  • Understanding of basic physics concepts, particularly power and force.
  • Familiarity with the formula for calculating power: Power = Force x Velocity.
  • Knowledge of gravitational force and its impact on motion.
  • Basic understanding of kinetic energy principles.
NEXT STEPS
  • Research the principles of kinetic energy and its relation to power calculations.
  • Learn about the effects of gravitational force on horizontal motion in physics.
  • Explore advanced power calculation techniques in dynamic systems.
  • Investigate the implications of resistance forces on train movement and energy consumption.
USEFUL FOR

Physics students, engineers, and professionals involved in transportation dynamics, particularly those interested in power calculations and energy efficiency in train systems.

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Homework Statement
'Find the max power of a train engine travelling level at 50 metres per second if total resistance to motion is 30 KiloNewtons.
Relevant Equations
'Find the max power of a train engine travelling level at 50 metres per second if total resistance to motion is 30 KiloNewtons.
In answer to this I get power = force times velocity so 30000 x 50 = 1500000 = 1.5 Mega Watts. My answer book says 1.47 Mega Watts. I can see how 1.5MW minus 30KW = 1500000 - 30000 = 1.47MW. Also I can see that power times gravity of 9.8 = 1.5 MW times 9.8 N gives the same answer. I can't see how you should subtract the force from the sum of the force and the distance, or how vertical gravity can reduce the speed of a horizontally moving train. Thanks :)
 
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