<span>Frequency of a sound wave is called the pitch. Higher frequencies have a higher pitch and lower frequencies have the opposite. When an ambulance travels by a listener, the frequencies are oscillating rapidly and causing the shrill, loud sounds that emanate from the sirens.</span>
The process of heat exchange is involved in the operation of all heat engines.
<u>Explanation:</u>
A heat engine refers as the system which converts thermal or heat and chemical energy into mechanical energy. Then, these can be utilised for mechanical work. This is done by raising the active substances from higher to lower temperature state. In simple words, it produces macroscopic movement from the heat.
For example, when people rub their hands, friction converts mechanical energy (the movement of our hands) into thermal energy (hands warm up). Heat engines work exactly the opposite; they take energy to warm up (in relation to the environment) and release it for movement. This movement is often transformed into electricity by a generator. It shows that there is exchange of heat involved in all of its processes.
Answer:19.5 J
Explanation:
Given
mass of block=3 kg
angular frequency=20 rad/sec
spring constant 
we know total energy remain conserved
Where 
=kinetic energy
=potential Energy
When mass reaches amplitude its velocity becomes zero
there is only potential energy which is equal to Total energy
Answer:
Explanation:
Given that
The window height is 2m
And the window is 7.5m from the ground
Then the total height of the window from the ground is 7.5+2=9.5m
It takes the ball 0.32sec travelled pass the window.
When the ball get to the window, it has an initial velocity (u') and when it gets to the top of the window it has a final velocity ( v')
Now using the equation of free fall during this window travels
S=ut-½gt² against motion.
S=2, g=9.81, t=0.32sec
Then,
S=u't-½gt²
2=u'×0.32-½×9.81×0.32²
2=0.32u'-0.5023
2+0.5032=0.32u'
Then, 0.32u'=2.5032
u'=2.5032/0.32
u'=7.82m/s
This is the initial velocity as the ball got the the window
Now, let analyse from the window bottom to the ground which is a distance of 7.5m
Using the equation of free fall again
v²=u²-2gH
In this case the final velocity (v) is the velocity when the ball reach the bottom of the window i.e u'=7.82m/s,
While u is the original initial velocity from the throw of the ball
Then,
u'²=u²-2gH
7.82²=u²-2×9.81×7.5
61.146=u²-147.15
61.146+147.15=u²
Then, u²=208.296
So, u=√208.296
u=14.43m/s
The initial velocity of the ball form the throw is 14.43m/s
