Calculating Kinetic Energy for a Sled and Rider on a Hill

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SUMMARY

The discussion focuses on calculating the kinetic energy of a sled and rider with a combined mass of 55 kg descending from a height of 20 m. Initially, the sled has a kinetic energy of 1950 J at the top of the hill. Ignoring friction, the total kinetic energy at the bottom of the hill is calculated by adding the potential energy (mgh) to the initial kinetic energy, resulting in a final kinetic energy of 11,950 J. The correct formula for potential energy is mgh, where g is the acceleration due to gravity (9.81 m/s²).

PREREQUISITES
  • Understanding of kinetic energy formula (k = 1/2 mv²)
  • Knowledge of potential energy calculation (PE = mgh)
  • Basic principles of energy conservation
  • Familiarity with gravitational acceleration (g = 9.81 m/s²)
NEXT STEPS
  • Study energy conservation principles in physics
  • Learn about the relationship between potential and kinetic energy
  • Explore the effects of friction on energy calculations
  • Investigate real-world applications of kinetic energy in sports and mechanics
USEFUL FOR

Students studying physics, educators teaching energy concepts, and anyone interested in the mechanics of motion and energy transformations.

JohnJay
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Homework Statement



A sled and rider with a combined mass of 55 kg are at the top of a hill a height of 20 m above the level ground below. The sled is given a push providing an initial kinetic energy at the top of the hill of 1950 J.

(c) If friction can be ignored, what will be the kinetic energy of the sled and rider be at the bottom of the hill?

Homework Equations



k = 1/2 m v (squared)

The Attempt at a Solution




1/5 x 55 x 20 (squared) = 11,000

But its wrong!
 
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V is the velocity not the height.
At the top of the hill the sledge has potential energy given by "m g h" this is converted into kinetic energy as it goes down the hill, and is added to the intial KE
You don't need to know the speed - athough you can work it out at the top and bottom if you like!
 

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