Math Problem Statement

A student places her 490 g physics book on a frictionless table. She pushes the book against a spring, compressing the spring by x = 9.80 cm, then releases the book. What is the book's speed as it slides away? The spring constant is 1550 N/m .

Solution

To find the speed of the book as it slides away, we can use the principle of energy conservation. When the student compresses the spring, it stores potential energy, which is then transferred to the book as kinetic energy when the spring is released.

Step-by-Step Solution

  1. Convert the Mass and Compression to SI Units:

    • Mass of the book: m=490 g=0.490 kgm = 490 \ \text{g} = 0.490 \ \text{kg}
    • Compression of the spring: x=9.80 cm=0.098 mx = 9.80 \ \text{cm} = 0.098 \ \text{m}
  2. Calculate the Potential Energy Stored in the Spring: The potential energy UU stored in a compressed (or stretched) spring is given by: U=12kx2U = \frac{1}{2} k x^2 where k=1550 N/mk = 1550 \ \text{N/m} is the spring constant, and x=0.098 mx = 0.098 \ \text{m} is the compression.

    Plugging in the values: U=12×1550×(0.098)2U = \frac{1}{2} \times 1550 \times (0.098)^2 U=12×1550×0.009604U = \frac{1}{2} \times 1550 \times 0.009604 U=7.4426 JU = 7.4426 \ \text{J}

  3. Apply Energy Conservation: The potential energy in the spring is converted to the kinetic energy of the book as it slides away: U=12mv2U = \frac{1}{2} m v^2 where vv is the speed of the book.

  4. Solve for the Speed vv: v=2Umv = \sqrt{\frac{2U}{m}} Substituting U=7.4426 JU = 7.4426 \ \text{J} and m=0.490 kgm = 0.490 \ \text{kg}: v=2×7.44260.490v = \sqrt{\frac{2 \times 7.4426}{0.490}} v=14.88520.490v = \sqrt{\frac{14.8852}{0.490}} v=30.3782v = \sqrt{30.3782} v5.51 m/sv \approx 5.51 \ \text{m/s}

Final Answer:

The speed of the book as it slides away is approximately 5.51 m/s\mathbf{5.51 \ m/s}.

Would you like further details on any part of this solution?


  1. How is energy conserved in spring and kinetic energy scenarios?
  2. How does spring compression affect potential energy?
  3. What changes if friction is added to this system?
  4. How does changing the spring constant affect speed?
  5. What role does mass play in determining speed?

Tip: In spring problems, always verify units, especially for displacement and mass, to ensure correct calculations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Physics
Energy Conservation
Kinetic Energy
Potential Energy in Springs

Formulas

Potential energy in a spring: U = 0.5 * k * x^2
Kinetic energy: KE = 0.5 * m * v^2
Conservation of energy: U = KE

Theorems

Conservation of Mechanical Energy

Suitable Grade Level

Grades 10-12