Answer:
Change in mechanical energy,
Explanation:
It is given that,
Mass of the projectile, m = 12 kg
Speed of the projectile, v = 20 m/s
Maximum height, h = 18 m
Initially, the projectile have only kinetic energy. it is given by :
K = 2400 J
Finally, it have only potential energy. it is given by :
P = mgh
P =2116.8 J
The change in mechanical energy is given by :
So, the change in mechanical energy is 283.2 J. Hence, this is the required solution.
To solve this problem we will apply the concepts related to Reyleigh's criteria. Here the resolution of the eye is defined as 1.22 times the wavelength over the diameter of the eye. Mathematically this is,
Here,
D is diameter of the eye
The angle that relates the distance between the lights and the distance to the lamp is given by,
For small angle,
Here,
d = Distance between lights
L = Distance from eye to lamp
For small angle
Therefore,
Therefore the distance is 5.367km.