Kinetics
A ball thrown vertically upward passes the same height, h, at 2s and 10s on its way up and down, respectively, Calculate h.

h = 98m

Explanation:

The ball follows a projectile motion.

It it's at the same height at t = 2 and t =10,

It was at a max height at:

t = (2+10)/2

= 12/2

= 6s

Conventional: upwards positive

s = ut + ½at²

s = ut + ½(-9.8)t²

s = ut - 4.9t²

s is equal at t = 2 and t = 10

2u - 4.9(2)² = 10u - 4.9(10)²

2u - 19.6 = 10u - 490

8u = 470.4

u = 58.8

at t = 2

s = 58.8(2) - 4.9(2)²

s = 98 m

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