Answer:
The speed of the air leaving the hairdryer is 10m/s.
Explanation:
The thrust that the dryer produces is what keeps it elevated at an angle of 5° from the vertical; therefore, from the force diagram we get

putting in
,
and solving for
we get:



Now, this thrust produced is related to to the air ejection speed
by the relation

where
is the rate of air ejection which we know is

and since
,


putting this into equation (2) and the value of
we get:

which gives


which is the speed of the air ejected.
Below are the choices that can be found in the other sources:
A. diffraction
<span>B. refraction </span>
<span>C. reflection </span>
<span>D. transmission
</span>
The answer is diffraction. It means that <span>the process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge, typically accompanied by interference between the wave forms produced.</span>
The stone's altitude at time
is given by

where
is the acceleration due to gravity. The stone reaches the ground when
:

Answer:
Pressure is equal to the ratio of thrust to the area in contact. Upthrust is a force exerted by the fluids on an object placed in the fluid . Upthrust acts in upward direction.
Explanation:
Given that,
Force with which a child hits a ball is 350 N
Time of contact is 0.12 s
We need to find the impulse received by the ball. The impulse delivered is given by :

So, the impulse is 42 N-m..
We know that he change in momentum is also equal to the impulse delivered.
So, impulse = 42 N-m and change in momentum =42 N-m.