Question:As we've seen, astronauts measure their mass by measuring the period of oscillation when sitting in...
Question
As we've seen, astronauts measure their mass by measuring the period of oscillation when sitting in...
As we've seen, astronauts measure their mass by measuring the period of oscillation when sitting in a chair connected to a spring. The Body Mass Measurement Device on Skylab, a 1970s space station, had a spring constant of 606 N/m. The empty chair oscillated with a period of 0.848 s.
What is the mass of an astronaut who oscillates with a period of 2.26 s when sitting in the chair?
The concept required to solve this problem is period of oscillation of an object in simple harmonic motion.
Initially, apply the formula for the period of oscillation and solve for the mass of the object. After that repeat, the same with new mass. Then for the mass of astronaut, subtract the masses obtained in both the steps.
Fundamentals
The period of oscillation T of an object oscillating is given as follows:
T=2πkm
Here, m is the mass of the object and k is the spring constant.
The period of oscillation T of an object oscillating is given as follows:
T=2πkm
Rearrange the expression for the mass of the object as follows:
m=(2πT)2k
Substitute 0.848s for T and 606N/m for k as follows:
m={2(3.14)0.848s}2(606N/m)=11.05kg
The expression for the mass of the object is given as follows:
m′=(2πT′)2k
Substitute 2.26s for T′ and 606N/m for k as follows:
m′={2(3.14)2.26s}2(606N/m)=78.40kg
So, the mass of the astronaut is given as follows:
M=m′−m
Substitute 78.40kg for m′ and 11.05kg for m as follows:
M=78.40kg−11.05kg=67.35kg
Ans:
The mass of the astronaut sitting on the chair is 67.35kg .