Let
be the speed of the helicopter in still air. Let
be the speed of the wind. Then, from the given information,

Adding the above 2 equations,

The speed of the helicopter in still air 
Answer:
Explanation:
Given
Maximum height H = 300m
Range (horizontal distance) = 380m
Required
Initial speed U and the angle of the ball when it was launched.
Range = U√2H/g
380 = U√2(300)/9.8
380 = U√600/9.8
380 = 7.8246U
U = 380/7.8246
U = 48.57m/s
The initial speed is 48.57m/s
b) Using the formula for calculating time of flight;
T = 2Usin theta/g
9 = 2(48.57)sin theta/9.8
9*9.8 = 97.14sin theta
88.2 = 97.14sin theta
88.2/97.14 = sin theta
sin theta = 0.9079
theta = sin^-1(0.9079)
theta = 65.23°
hence the angle when the ball was launched is 65.23°
Answer:
a) Current.
Explanation:
The "junction rule" (Kirchhoff's first law) says that the value of the electric current entering any point in the circuit must be the same as the one leaving it. This comes as a consequence of the conservation of charge, the electric charge that comes in must come out (when speaking about currents, per unit time).