Answer:29.627 m
Explanation:
Given
Initial velocity of life preserver(u) is 1.6 m/s
it takes 2.3 s to reach the water
using equation of motion
v=u+at

v=24.163 m/s
Let s be the height of life preserver



s=29.627 m
Answer:
B. 7.07 m/s
Explanation:
The velocity of the stone when it leaves the circular path is its tangential velocity,
, which is given by

where
is the angular speed and
is the radius of the circular path.
is given by

where
is the frequency of revolution.
Thus

Using values from the question,

<em>Note the conversion of 75 cm to 0.75 m</em>

Answer:
A. The upward pressure gradient force is balanced by gravity.
Explanation:
A. is correct because the pressure difference is actually generated by gravity. As in the following formula for the pressure at different points:

where
are the pressure at 2 points, ρ is the density of the fluid, g is the gravitational constant, and h is the height difference.
B is incorrect because friction in air is too small to make an effect.
C is incorrect because the Coriolis force is horizontal, not vertical.
D is incorrect because a difference of 500 hPa = 50000 Pa, this is half of the atmospheric pressure.
E is incorrect because temperature cannot generate force.