# Use vibration to calculate mass in space

1. Mar 11, 2009

### pchase0

an astronaut in space sits on a chair that vibrates horizontally at the end of a spring. the spring has a 1200-N/m spring constant, the amplitude of vibration is 0.50 m and the speed of the chair as it passes through equilibrium is 2.0 m/s.

also devise another method to determine the mass, you know the spring constant of the spring-seat (1200-N/m) and the mass of the vibrating seat on which she sits. you also have a stop watch. describe the method and do a sample calculation

2. Mar 11, 2009

### Dr.D

so what have you done? Don't know any girl astronauts?

3. Mar 11, 2009

### pchase0

i dont know how to approach either

4. Mar 11, 2009

### Dr.D

Forget the girl, what do you know about simple harmonic motion?

You have a mass vibrating on the end of a spring, where you know the spring constant, the amplitude of vibration, and the speed when the chair passes through equilibrium. Write the equation of motion and the general solution, then express each of the known conditions in terms of the general solution, and see if you can find the mass of the chair and occupant (male or female) from what results.

5. Mar 11, 2009

### pchase0

im still lost on where to even begin