Skip to main content
Ch 14: Periodic Motion
Chapter 14, Problem 14

A small block is attached to an ideal spring and is moving in SHM on a horizontal, frictionless surface. When the amplitude of the motion is 0.090 m, it takes the block 2.70 s to travel from x = 0.090 m to x = -0.090 m. If the amplitude is doubled, to 0.180 m, how long does it take the block to travel (a) from x = 0.180 m to x = -0.180 m?

Verified step by step guidance
1
Identify the type of motion: The block is moving in Simple Harmonic Motion (SHM), which is characterized by its sinusoidal motion and dependence on the spring's properties.
Understand the relationship between amplitude and period in SHM: The period of SHM is independent of the amplitude. This means that even if the amplitude changes, the period of the oscillation remains the same.
Recall the definition of period in SHM: The period (T) is the time it takes for the block to complete one full cycle of motion, from one extreme to the other and back again.
Apply the information given in the problem: Since the period is independent of amplitude, the time taken to travel from x = 0.180 m to x = -0.180 m will be the same as the time taken to travel from x = 0.090 m to x = -0.090 m, which is given as 2.70 seconds.
Conclude that the time taken for the block to travel from x = 0.180 m to x = -0.180 m when the amplitude is doubled is also 2.70 seconds.

Verified Solution

Video duration:
4m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Simple Harmonic Motion (SHM)

Simple Harmonic Motion is a type of periodic motion where an object oscillates around an equilibrium position. The motion is characterized by a restoring force proportional to the displacement from the equilibrium, leading to sinusoidal motion. In SHM, the period and frequency are constant, depending only on the system's properties, such as mass and spring constant.
Recommended video:
Guided course
07:52
Simple Harmonic Motion of Pendulums

Amplitude

Amplitude refers to the maximum extent of displacement from the equilibrium position in oscillatory motion. In the context of SHM, it is the maximum distance the block moves from its rest position. Doubling the amplitude increases the distance the block travels during each oscillation, but it does not affect the period of the motion, which remains constant for a given system.
Recommended video:
Guided course
04:24
Amplitude Decay in an LRC Circuit

Period of Oscillation

The period of oscillation is the time taken for one complete cycle of motion in SHM. It is independent of the amplitude for ideal springs and is determined by the mass of the block and the spring constant. The formula for the period (T) in SHM is T = 2π√(m/k), where m is the mass and k is the spring constant, indicating that changes in amplitude do not affect the period.
Recommended video:
Guided course
06:28
Satellite Period
Related Practice
Textbook Question
In a physics lab, you attach a 0.200-kg air-track glider to the end of an ideal spring of negligible mass and start it oscillating. The elapsed time from when the glider first moves through the equilibrium point to the second time it moves through that point is 2.60 s. Find the spring's force constant.
1757
views
Textbook Question
A 2.00-kg, frictionless block is attached to an ideal spring with force constant 300 N/m. At t = 0 the spring is neither stretched nor compressed and the block is moving in the negative direction at 12.0 m/s. Find (a) the amplitude and (b) the phase angle. (c) Write an equation for the position as a function of time.
2220
views
2
rank
Textbook Question
The point of the needle of a sewing machine moves in SHM along the x-axis with a frequency of 2.5 Hz. At t = 0 its position and velocity components are +1.1 cm and -15 cm/s, respectively. (a) Find the acceleration component of the needle at t = 0.
755
views
Textbook Question
Weighing Astronauts. This procedure has been used to 'weigh' astronauts in space: A 42.5-kg chair is attached to a spring and allowed to oscillate. When it is empty, the chair takes 1.30 s to make one complete vibration. But with an astronaut sitting in it, with her feet off the floor, the chair takes 2.54 s for one cycle. What is the mass of the astronaut?
910
views
Textbook Question
A 0.400-kg object undergoing SHM has ax = -1.80 m/s^2 when x = 0.300 m. What is the time for one oscillation?
875
views
1
rank
Textbook Question
A 0.500-kg mass on a spring has velocity as a function of time given by vx(t) = -(3.60 cm/s) sin[(4.71 rad/s)t - (pi/2)]. What are (a) the period; (b) the amplitude; (c) the maximum acceleration of the mass; (d) the force constant of the spring?
1567
views