Measuring the mass of
an astronaut
TP
TP
Doppler Effect
(red shift et bleu shift)
rotation period of Mercury
TPMeasure of the differential rotation
of the Sun by observing solar spots
Δ
TPRemote
sensing
The mass of a black holeTP
Elliptic motion (a)
Period (T)
3°Kepler law
Reference star
TP
http://eoedu.belspo.be/fr/profs/index.htm
Huriccane speed
Boyle et Mariotte
TP
freefall study
(T48) Matteo Siccardi: Apllet Geogebra
Screencasting
Measuring the mass of an astronaut
Why measuring the mass?
• For the look ?
Why measuring the mass?
• osteoporosis ?
zero gravity
weightless
environment
Why measuring the mass?
• For EVA (Extra Vehicular Activity)?
spacesuit
Problem?
zero gravity
Harmonic motion
harmonic oscillators
A suspended from a spring
(translation oscillator) object
can oscillate on either side of
an equilibrium position.
0
- Max
+ Max
All periodic oscillating movements "can be assimilated" to the projection on an axis of
a turning point X at constant speed on a "trigonometric" circle of radius R = Max.
0
- Max
+ Max
yy
: angular speed (rad/s)
t: time (s)
: angle
= .t
y=Y.sin( )
Where:
Y: amplitude
: pulsation
.t: phase
y: gives the position, the value of an electric field, pressure, ....
It is possible to calculate the speed at which the position varies, the electric field or
pressure, ... during a time interval t.
We can also calculate how the speed varies during time interval t.
To get an accurate speed and instant acceleration, just use a very small t that the limit
tends to zero, or just take the derivative with respect to time.
The speed
L’accélération
Dynamics of the harmonic oscillator
remark:
The time (and therefore frequency) is independent of the amplitude (A)
Spring constant
Force sensor