The velocity of the rock after 2s is 12.56 m/s.
The velocity of the rock at 25 m upwards is 14.68 m/s.
The velocity of the rock at 25 m downwards is -15.97 m/s.
The given parameters;
- <em>velocity of the rock, u = 20 m/s</em>
- <em>height of the rock, h = 20t - 1.8t²</em>
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The velocity of the rock after 2s is calculated as follows;

The velocity of the rock when the height is 25 m:
h = 20t - 1.8t²
25 = 20t - 1.8t²
1.8t² - 20t + 25 = 0
solve for the time of motion "t" using quadratic formula
a = 1.8, b = -20, c = 25

The value of t that will give 25 m upwards using the motion model is 1.43 s;
h = 20(1.43) - 1.86(1.43)² = 25 m
The velocity of the rock at 25 m upwards (t = 1.43 s) is calculated as follows;

The velocity of the rock at 25 m downwards (t = 9.67 s) is calculated as;

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Answer:

Explanation:
The force of gravity acting on the satellite is given by:

where
G is the gravitational constant
is the Earth's mass
m is the mass of the satellite
r is the distance of the satellite from the Earth's centre
Here we have
m = 700 kg

Substituting into the equation, we find:

<em>Note that the distance mentioned in the problem (2.4 x 10^6 meters) is not realistic, since it is less than the radius of the Earth (6.37 x 10^6 meters).</em>
Answer:
its a liquid
Explanation:
liquid means water water means liqiud without them we cannot survive we need to be healthy we should bath we should drink more amount of water
Answer:
The energy of motion is called is kinetic energy.