Answer:
Explanation:
In this problem we have three important moments; the instant in which the ball is released (1), the instant in which the ball starts to fly freely (2) and the instant in which has its maximum height (3). From the conservation of mechanical energy, the total energy in each moment has to be the same. In (1), it is only elastic potential energy; in (2) and (3) are both gravitational potential energy and kinetic energy. Writing this and substituting by known values, we obtain:
Since we only care about the velocity 
, we can keep only the second and third parts of the equation and solve:
So, the speed of the ball just after the launch is 17.3m/s.
diesel engines do not use spark plugs because diesel has more oil, burns slower, and is more difficult to ignite. Therefor spark plugs are insufficient with just spark so instead they use glow plugs witch provides a high amount of heat to the fuel and ignites more quickly and reliably.
<span>The amount of compression pressure in a diesel engine is sufficient to produce enough heat to ignite the fuel. The glow plugs are only used on a cold start.</span>
-- The density of the glass alone doesn't change.
-- The density of the water alone doesn't change.
-- The density of (the entire glass + everything IN IT) increases,
because the part that used to be air (with very low density) is
changed to water (with much higher density than the air had).
