Answer= 8m/s
Because total Momentum before= total momentum after
Momentum before (p=mu)
p=(4)(12)= 48
p=2(0)=0
So total momentum before=48
Momentum after (p=mu)
Masses combined —2+4=6kg
p=6u
Mb=Ma
48=6u
u=8m/s
Sunlight, because it provides a source of energy is the answer because plants also provide a food source (please put as brainliest answer)
A=m/s^2(meter per second square)
Work=joule
It is a theory on a show that people try to solve.
Answer:


Explanation:
Wave 1, 
Wave 2, 
Wave 3, 
Wave 4, 
The general equation of travelling wave is given by :

The value of
will remain the same if we take phase difference into account.
For first wave,



For second wave,



For the third wave,



For the fourth wave,



It is clear from above calculations that waves 1 and 3 have same time period. Also, wave 2 and 4 have same time period. Hence, this is the required solution.