Doppler shifted hydrogen absorption lines are seen in the spectrum of a star.
the hydrogen line at 656.28 nm is seen to be shifted to 656.08 nm.
how fast is the star moving (note: the speed of light is approximately 300,000 km/s, or 3 × 105
km/

a) about 1,000 km/s
b) about 1,000,000 km/s
c) about 100 km/s
d) about 10,000 km/s

Explanation:

It is given that,

Wavelength of hydrogen line,

Shift in wavelength,

According to Relativistic Doppler Effect, the shift in wavelength is given by :

v is the speed of star

c is the speed of light

or

v = 91.43 km/s

So, the star is moving with a speed of about 100 km/s. Hence, this is the required solution.

the chart show the masses and velocities of two colliding objects that stick together after a collision.

according to the law of conservation of momentum, the momentum of the object after the collision is  

answer

1,500

kg • m/s.

prndulum needs thread, weight clock to time swings