Answer:
Light is one of nature's ways of moving energy from one place to another.
Explanation:
It has no substance, or mass. How does light travel? Light behaves like a traveling wave, something like waves in a string or on the surface of water.
Use conservation of momentum ;
m1u1 + m2u2 = m1v1 + m2v2
1200×15.6 + 0 = 2700v
v = 18720/2700
v = 6.933 or ~ 7 m/s
according to conservation of momentum , in absence of external forces , the total momentum of system of the particles remain same both before and after collision.
momentum of colliding objects before collision = momentum of colliding objects after collision.
or
m1 v1i + m2 v2i = m2 v1f + m2 v2f
where m1 and m2 are the two colliding objects. v1i and v2i are their respective initial velocities before collision and v1f and v2f are their respective final velocities after collision.
hence the correct statement is
total momentum before the collision is equal to the momentum after collision.
This is due to the Doppler effect. The position you are in regard to the sound wave causes a change in the amplitude which affects frequency and moves the pitch up