Skip to main content
Ch 14: Periodic Motion
Young & Freedman Calc - University Physics 14th Edition
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610당신이 사용하는 게 아니라요?교과서 변경
14장, 문제 17

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?

검증된 단계별 안내
1
First, understand that the problem involves a mass-spring system where the period of oscillation is related to the mass attached to the spring. The formula for the period \( T \) of a mass-spring system is given by: \( T = 2\pi \sqrt{\frac{m}{k}} \), where \( m \) is the mass and \( k \) is the spring constant.
Calculate the spring constant \( k \) using the period of the empty chair. Rearrange the formula to solve for \( k \): \( k = \frac{4\pi^2 m}{T^2} \). Substitute \( m = 42.5 \text{ kg} \) and \( T = 1.30 \text{ s} \) to find \( k \).
Next, use the period of the chair with the astronaut to find the total mass \( m_{total} \) (chair plus astronaut). Use the same formula for the period: \( T = 2\pi \sqrt{\frac{m_{total}}{k}} \). Substitute \( T = 2.54 \text{ s} \) and the previously calculated \( k \) to solve for \( m_{total} \).
The total mass \( m_{total} \) is the sum of the mass of the chair and the mass of the astronaut. Therefore, \( m_{total} = m_{chair} + m_{astronaut} \). Rearrange this to solve for the mass of the astronaut: \( m_{astronaut} = m_{total} - m_{chair} \).
Substitute the known values into the equation to find the mass of the astronaut. Use the calculated \( m_{total} \) and the given \( m_{chair} = 42.5 \text{ kg} \) to find \( m_{astronaut} \).

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
7m
도움이 되었나요?

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Simple Harmonic Motion

Simple harmonic motion (SHM) describes the oscillatory motion of objects like springs and pendulums. It is characterized by a restoring force proportional to the displacement from equilibrium, resulting in sinusoidal oscillations. The period of oscillation depends on the mass and the spring constant, which is crucial for determining the mass of the astronaut in this scenario.
추천 영상:
07:52
Simple Harmonic Motion of Pendulums

Spring Constant

The spring constant, denoted as k, measures the stiffness of a spring and is defined by Hooke's Law, F = -kx, where F is the force applied, and x is the displacement. In the context of oscillations, the spring constant influences the period of vibration, allowing us to relate the change in period to the mass of the astronaut.
추천 영상:
08:59
Phase Constant of a Wave Function

Period of Oscillation

The period of oscillation is the time taken for one complete cycle of motion. It is determined by the formula T = 2π√(m/k), where m is the mass and k is the spring constant. By comparing the periods with and without the astronaut, we can calculate her mass using the change in oscillation period.
추천 영상:
06:28
Satellite Period
관련 실천
교과서 질문

A 0.400-kg object undergoing SHM has ax = -1.80 m/s2 when x = 0.300 m. What is the time for one oscillation?

1781
views
1
rank
교과서 질문

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 from x = 0.180 m to x = -0.180 m?

2809
views
교과서 질문

A 0.500kg0.500\(\operatorname{kg}\) mass on a spring has velocity as a function of time given by vx(t)=(3.60cm/s)sin[(4.7 rad/s)t(π/2)]v_{x}(t)=-(3.60\(\operatorname{cm}\)/s)\(\sin\)[(4.7\(\text{ }\)rad/s)t-(\(\pi\)/2)]. What are the period and the force constant of the spring?

1593
views
교과서 질문

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 from x = 0.090 m to x = -0.090 m?

1748
views
교과서 질문

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. Find the acceleration component of the needle at t = 0.

1567
views
1
rank
교과서 질문

A 0.500kg0.500\(\operatorname{kg}\) mass on a spring has velocity as a function of time given by vx(t)=(3.60cm/s)sin[(4.7 rad/s)t(π/2)]v_{x}(t)=-(3.60\(\operatorname{cm}\)/s)\(\sin\)[(4.7\(\text{ }\)rad/s)t-(\(\pi\)/2)]. What are the amplitude and the maximum acceleration of the mass?

2484
views