Answer:
a)
b) 
Explanation:
a) The displacement of the first object is 22.5 m, so we can use the next equation:



positive acceleration.
b) Using the same equation we can find the second value of the acceleration:


positive acceleration.
I hope it helps you!
Answer:
person when the point-light walker is moving
Explanation:
A point light walker is an arrangement of dots that moves in a way that mimics a human walking. This is used in the field of Biological Motion Perception.
Biological motion perception is the science that deals with how our brain perceives motion. In order to understand how the brain perceives motion a point light walker is used.
Answer:
iv) It is 9x bigger than before
Explanation:
As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:
At = A + 4A -2A = 3 A
The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:
I = P/A
where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)
For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.
If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.
So, the statement iv) is the right one.
I'm pretty sure its Venus!!!