Energy at top = m*g*height at top from release point
=0.16*9.81*11.6
=18.21J
At release kinetic energy= Gravtiational energy at top
1/2*0.16*v^2=18.21J
v^2=227.625
v=15.10m/s
A because it is a formula for h*2
In rivers that are close to sea
(1) Speed is the ratio of the total distance covered by the object and the total time it takes for him to finish it.
Speed = distance / time
In this item, we are given that the distance is 20 kilometers and that the time it takes for the trip is 2 hours. Substituting the known values,
Speed = 20 kilometers / 2 hours
speed = 20 km/h
(2) Velocity on the other hand takes into account the displacement of the object from his original position. It is assumed that Jeremie was basically back to his original position after two hours. Hence, the velocity is equal to zero.
Well, all the words are common, but I try to answer in my way. The way how light is used to study space is finding distance between the planets, which is called a light year. According to the <span>scientist's beliefs the space is but a vaccum and the only body that can travel through it is light, that's why light is very importand for discovering space.
</span>Hope you will find it helpful!