Answer: Height of building = 17.69m, velocity of brick = 18.6m/s
Explanation: From the question, the body has a zero initial speed, thus initial velocity (u) all through the motion is zero.
By ignoring air resistance makes it a free fall motion thus making it to accelerate constantly with a value of 
.
Time taken to fall = 1.90s
a)
thus the height of the building is calculated using the formulae below
but u = 0 , hence
b)
to get the value of velocity (v) as the brick hits the ground, we use the formulae below
but u= 0, hence
find the attachment in this answer for the accleration- time graph, velocity- time graph and distance time graph
Explanation :
As the ambulance got closer, Marge noticed that the pitch of the siren got higher. This is due to the Doppler's effect.
The siren of the ambulance has a higher pitch when it approaches Marge. When the waves move away from him, it will have a lower pitch.
As the waves come closer to us, the waves become compressed and hence the frequency of the wave increases.
4 significant figures (the 0’s are considered significant because they follow a non-zero number)
Answer:
option B
Explanation:
When you rub a clear plastic pen with the wool the plastic pen gets charges this phenomenon is known as frictional charging.
Due to rubbing, the pen gets negatively charged.
We know, opposite charge attract each other and the same charge repel each other.
So, when the pen is negatively charged the tape might be positively charged or the tape might be uncharged.
Hence, the correct answer is option B
