In Space, an astronaut releases a wrench from his hand. The wrench has a mass of 4 grams and is traveling with a velocity of -15m/s. The Astronaut’s mass is 70kg. What is his Velocity?

Explanation:

We have,

Mass of a wrench, m₁ = 4 g = 0.004 kg

Speed of wrench, v₁ = -15 m/s

Mass of the Astronaut, m₂ = 70 kg

It is required to find Astronaut's velocity. Let it is v₂. Using the conservation of linear momentum to find it.

So, his velocity is .

f=ma newton's second law 7x8=56n

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me