The component of waves must have same frequency and phase.
when the component of waves vibrate at the same rate and attain maximum point at the same time, reinforcement of the waves amplitude occur to cause a constructive interference.However, when the two waves are out of phase where one is at minimum when the other is at maximum a destructive interference happens.
Answer:
Explanation:
Given
Initial speed is u=V
Maximum height of Pebble is H
Deriving maximum height of Pebble and considering motion in vertical direction

where v=final velocity
u=initial velocity
a=acceleration
s=Displacement
Final velocity will be zero at maximum height


i.e. maximum height is dependent on square of initial velocity
for twice the height

on comparing
Answer:
Width of the slit will be equal to 1.47 mm
Explanation:
We have given wavelength of the light 
Distance D = 8 m
Distance between first minimum dark fringe and the central maximum is 2 mm
So 
We have to find the width of the slit
For the first order wavelength is equal to
, here a width of slit
So 
So width of the slit will be equal to 1.47 mm
To solve this problem it is necessary to apply the kinematic equations of motion.
By definition we know that the position of a body is given by

Where
Initial position
Initial velocity
a = Acceleration
t= time
And the velocity can be expressed as,

Where,

For our case we have that there is neither initial position nor initial velocity, then

With our values we have
, rearranging to find a,



Therefore the final velocity would be



Therefore the final velocity is 81.14m/s
Answer:
acceleration 8 km/h/s south
Explanation:
First of all, let's remind that a vector quantity is a quantity which has both a magnitude and a direction.
Based on this definition, we can already rule out the following two choices:
distance: 40 km
speed: 40 km/h
Since they only have magnitude, they are not vectors.
Then, the following option:
velocity: 5 km/h north
is wrong, because the car is moving south, not north.
So, the correct choice is
acceleration 8 km/h/s south
In fact, the acceleration can be calculated as

where
v = 40 km/h is the final velocity
u = 0 is the initial velocity
t = 5 s is the time
Substituting,

And since the sign is positive, the direction is the same as the velocity (south).