Elastic Potential Energy Problem

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SUMMARY

The discussion focuses on calculating the compression of a spring in a laboratory cart scenario, where a 1.2 kg cart with a spring constant of 65.0 N/m is initially compressed by 8.0 cm. The equation used is (1/2)mv^2=(1/2)kx^2, leading to an initial calculation of 5.71 cm for the spring's compression at a velocity of 42.0 cm/s. However, the correct answer is 5.6 cm, which accounts for the initial compression of the spring. This adjustment is crucial for accurate energy calculations in elastic potential energy problems.

PREREQUISITES
  • Understanding of elastic potential energy and the formula (1/2)kx^2
  • Basic knowledge of kinetic energy and the formula (1/2)mv^2
  • Familiarity with spring constants and their significance in physics
  • Ability to manipulate equations to solve for unknown variables
NEXT STEPS
  • Study the principles of conservation of energy in mechanical systems
  • Learn about the relationship between kinetic energy and potential energy in spring systems
  • Explore advanced applications of Hooke's Law in real-world scenarios
  • Practice solving problems involving multiple energy states in physics
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Students studying physics, particularly those focusing on mechanics and energy conservation, as well as educators looking for practical examples of spring dynamics.

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Homework Statement


A 1.2 kg spring laboratory cart is held against a wall. The spring constant is 65.0 N/m. The spring is compressed 8.0 cm when held against the wall. What is the compression of the spring when the cart's velocity is 42.0 cm/s?


Homework Equations


(1/2)mv^2=(1/2)kx^2


The Attempt at a Solution



(1.2)(0.42)^2=65(x)^2
x=5.71 cm

But the answer says 5.6 cm, so I think I did something wrong.
 
Physics news on Phys.org
Since the cart is starting out already compressed to 8cm, you would have to consider that initial displacement in your equation. Subtract the final elastic potential energy from the original (x=8cm) elastic potential energy on the right side. Do that and you should get 5.6cm.
 

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