nuclear fusion- produces huge amounts of energy.
Answer:

Explanation:
We know that speed is given by dividing distance by time or multiplying length and frequency. The speed of the father will be given by Lf where L is the length of the father’s leg ad f is the frequency.
We know that frequency of simple pendulum follows that 
Now, the speed of the father will be
while for the child the speed will be 
The ratio of the father’s speed to the child’s speed will be

The answer is:
C. 361 m/s
The explanation:
To calculate the speed of sound at a given temperature (50°C) we are going to use this formula:
v = 331 + 0.6T
when V is the velocity
and T is the temperature = 50°C
by substitution:
v = 331 + 0.6(50)
v = 361 m/s
So, The correct answer is C.
because of the variation of the motion of the molecules of air with change of temperature so, the velocity (V) of the sound in the air is change with temperature.
The correct answer should be A
Answer:
c. P₁/T₁=P₂/T₂
Explanation:
neither Avogadro’s, Charles’, or Boyle’s law formula can be used, since some parameters like volume is not given,
to find P₂, given P₁, T₁, and T₂ we will therefore use Gay-lussac's law.
gay lussacs law state that, provided volume is kept constant, pressure is directly proportional to temperature.
the volume volume is said to be filled, i.e its is kept constants when temperature is change