<h2>Answer: Resonance
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Resonance is a phenomenon that occurs when a body capable of vibrating is subjected to the action of a periodic force, whose frequency of vibration approaches the characteristic frequency of vibration (called resonance frequence) of said body. This is due a relatively small force applied in a repeated form, causing the amplitude of the oscillating system to become very large.
In other words, for the specific case of sound waves, this phenomenon occurs when the frequency of the wave that is external to the system or body coincides with the resonance frequency (characteristic frequency that reaches the maximum degree of oscillation) of this system or body.
In these circumstances the body vibrates, progressively increasing the amplitude of movement after each successive actions of the force. However, this effect can be destructive in some rigid materials.
Answer:
W=315 x 10⁵ J
Explanation:
Given that
F= 2.5 x 10⁵ N
d= 90 m
K.E.=5.4 x 10⁷ J
We know that work done by all force is equal to the change in kinetic energy
Lets take work done by catapult is W
W + F.d= K.E.
W= 5.4 x 10⁷ - 2.5 x 10⁵ x 90 J
W= (540 - 25 x 9) 10⁵ J
W=315 x 10⁵ J
Vi=0m/s
Vf=?
A=9.81
D=44
T=not needed
Vf^2=Vi^2+2ad
Vf=2ad square rooted
Vf=2(9.81)(44) square root it
Vf=29.3m/s
The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:

The total distance covered is

while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so

Therefore, the average velocity is