The answer is D. As the ambulance gets closer, the sound waves are compressed relative to the person; so the frequency increases.
Answer:
acceleration
Explanation:
The rate at which velocity changes is the definition of the physical quantity called acceleration, and it is given by the formula: 
where 
is the time that took to change from the initial velocity 
to the final velocity 
Answer:
warmer
Explanation:
The law of conservation of energy tells us that energy cannot be created or destroyed, it can be transferred or converted from one from to another. In this question when the beer that is at room temperature is put in the fridge, it loses some heat energy. This heat energy is not destroyed, the fridge through multiple processes eventually releases this heat to the room through pipes at the back which is why they are normally warm. the heat from the food inside is expelled to the room. It is not lost.
<h2>
A N S W E R : –</h2>
Nothing happens to the brightness of the light bulbs in the parallel circuit if the power supply is capable of supplying the additional current.
<span>A light-year is the total distance that light can travel in 1 year.
Since, We know the speed of light (c) in vacuum= 299792458 metres per second
And, there are 365.25 days in an year, or t= (365.25*24*60*60) seconds
Hence a light-year (d)=c*t
=299792458Ă—365.25Ă—24Ă—60Ă—60 metres
=9,460,730,472,580,800 metres
â‰9.46073Ă—10^15 metres</span>
