Frequency= velocity of light/wave length
Fr= 3×10^8/510×10^-9
Frequwency=5.88×10^14 Hz
The goalkeeper at his goal cannot kick a soccer ball into the opponent’s goal without the ball touching the ground
Explanation:
Consider the vertical motion of ball,
We have equation of motion v = u + at
Initial velocity, u = u sin θ
Final velocity, v = 0 m/s
Acceleration = -g
Substituting
v = u + at
0 = u sin θ - g t

This is the time of flight.
Consider the horizontal motion of ball,
Initial velocity, u = u cos θ
Acceleration, a =0 m/s²
Time,
Substituting
s = ut + 0.5 at²

This is the range.
In this problem
u = 30 m/s
g = 9.81 m/s²
θ = 45° - For maximum range
Substituting

Maximum horizontal distance traveled by ball without touching ground is 45.87 m, which is less than 95 m.
So the goalkeeper at his goal cannot kick a soccer ball into the opponent’s goal without the ball touching the ground
I think the correct answer would be that Charles' law explains why <span>a balloon deflates when the air around it cools. Charles' law is a simplification of the ideal gas law. At constant pressure, volume and temperature have a direct relationship. Hope this helps.</span>
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Answer:
A kilowatt (kW) is a unit of power.
Explanation:
The power of an object is given by :

Here,
E is the energy required
t is time
The SI unit of power is Watts and the SI unit of energy is Joule. the commercial unit of energy is kilowatt per hour.
Option (1) : A kilojoule (kJ) is a unit of power is incorrect.
Option (2) : A gigawatt (GW) is a unit of energy is incorrect.
Option (3) : A watt (W) is a unit of energy is incorrect.
Option (4) : A kilowatt x hour per year (kWh/yr) is a unit of energy is incorrect.
Option (4) : A kilowatt (kW) is a unit of power is correct.
Hence, the correct option is (d).