<span>a) 1960 m
b) 960 m
Assumptions.
1. Ignore air resistance.
2. Gravity is 9.80 m/s^2
For the situation where the balloon was stationary, the equation for the distance the bottle fell is
d = 1/2 AT^2
d = 1/2 9.80 m/s^2 (20s)^2
d = 4.9 m/s^2 * 400 s^2
d = 4.9 * 400 m
d = 1960 m
For situation b, the equation is quite similar except we need to account for the initial velocity of the bottle. We can either assume that the acceleration for gravity is negative, or that the initial velocity is negative. We just need to make certain that the two effects (falling due to acceleration from gravity) and (climbing due to initial acceleration) counteract each other. So the formula becomes
d = 1/2 9.80 m/s^2 (20s)^2 - 50 m/s * T
d = 1/2 9.80 m/s^2 (20s)^2 - 50m/s *20s
d = 4.9 m/s^2 * 400 s^2 - 1000 m
d = 4.9 * 400 m - 1000 m
d = 1960 m - 1000 m
d = 960 m</span>
Given :
Initial velocity , u = 0 m/s .
Acceleration due to gravity on moon , 
.
Height , h = 2 m .
To Find :
Final position after falling for 1.5 seconds .
Solution :
We know , by equation of motion :
Here , 
.
So , equation will transform by :
Therefore , the height form moon's surface is 1.88 m .
Hence , this is the required solution .
<h2>Answer </h2>
<h3>1) iron </h3>
<h3>2) Aluminium </h3>
<h3>3) sliver </h3>
<h3>4) copper </h3>
I hope it's helpful for you ☺️
A longitudinal wave is a wave that vibrates the medium in the same direction in which the wave energy travels.
The answer would be C.
