Answer:
55 kg
Explanation:
spring constant (k) = 600 N/m
mass of chair (Mc) = 12 kg
period of oscillation of chair and man (T) = 2.1 s
what is the mass of the astronaut (Ma) ?
mass of the astronaut (Ma) = total mass (Mt) - mass of chair (Mc)
where
- total mass (Mt) =
taking π as 3.142
total mass (Mt) = 
total mass (Mt) = 67 kg
therefore
mass of astronaut = 67 - 12 = 55 kg
When I ride the train, the song of the train whistle is an example of the Doppler Effect. Because a train is at the center of sound waves it produces, which radiate in concentric circles around it, there is no difference between the sound heard by someone on the platform, and the sound of the train as heard by someone standing behind the caboose.
Answer:The total variation in the amount of light entering our eye is not dectiable therefore planets do not twinkle.
Explanation:Stars twinkle, while planets (usually) shine steadily. Why? Stars twinkle because … they're so far away from Earth that, even through large telescopes, they appear only as pinpoints. ... Planets shine more steadily because … they're closer to Earth and so appear not as pinpoints, but as tiny disks in our sky.As light from a star races through our atmosphere, it bounces and bumps through the different layers, bending the light before you see it. Since the hot and cold layers of air keep moving, the bending of the light changes too, which causes the star's appearance to wobble or twinkle.
