Answer:
W= F × d
W= 2kn × 3.6
W= 7.2 J
Work is measured in Joules!
Gain in decibels is given by;
Gain db = 10*log (Po/Pi), where Po = Power output, Pin = Power input
Substituting;
Gain in db = 10 * log (50/5) = 10 db
The superscripts in a chemical formula are the overall charge of an ion
If ball remains in air for total time T = 0.85 s
this is also known as time of flight
In order to find the time of flight we can use kinematics

so for complete motion its displacement in y direction will be zero



now we know that net velocity of the ball is 8 m/s
while is y direction component we got is vy = 4.165 m/s
now by component method we can say




so it is projected at an angle of 31.4 degree above horizontal