Answer : Height, h = 20.4 m
Explanation :
It is given that,
Mass of an object, m = 500 g = 0.5 kg
Gravitational potential energy, PE = 100 J
The Gravitational potential energy is the energy which is possessed due to the height and gravity of an object. It is given as :
PE = m g h
where,
h is the height of the cliff.

h = 20.40 m
So, the height of the cliff is 20.4 m.
Answer: As Earth spins on its axis, we, as Earth-bound observers, spin past this background of distant stars. As Earth spins, the stars appear to move across our night sky from east to west, for the same reason that our Sun appears to “rise” in the east and “set” in the west.
Explanation:
<span>The Earth’s orbit is a nearly circular ellipse.
</span><span>The Sun is located at one of the two focal points.</span>
The Earth moves around the Sun in an orbit that is almost but not quite circular. As Kepler proved in the seventeenth century, the orbit is actually an ellipse. A parameter called the eccentricity (e) defines the degree of departure from a circle. A value of e=0 would indicate a circle whereas a value of e=0.9 would indicate a very elongated ellipse. The eccentricity of the Earth's orbit is currently e=0.0167.
In 2.34 hours, the bus travels 16.34 km.
Average speed = (distance covered) / (time to cover the distance).
Average speed = (16.34 km) / (2.34 hours) = 6.983 km/hr