D = 1/2 g t^2. It works out to 44.1 meters.
Answer:
In an elastic collision:
- There is no external net force acting. Thus, Momentum before and after collision is equal. Momentum remains conserved.
- Total energy always remains conserved as energy cannot be created nor destroyed. It can change from one form to another.
- There is no lost due to friction in elastic collision. So the kinetic energy is also conserved.
- Velocities may change after collision. If the masses are equal, the velocities interchange.
When one object is stationary:
Final velocity of object 1:
v₁ = (m₁ - m₂)u₁/(m₁ +m₂)
Final velocity of object 2:
v₂ = (2 m₁ u₁)/(m₁+m₂) =
- Objects do not stick together in elastic collision. They stick together in inelastic collision.
- One object may be stationary before the elastic collision.
Thus, conditions for an elastic collision:
- Energy is conserved.
- Velocities may change.
- Momentum is conserved.
- Kinetic energy is conserved.
- One object may be stationary before the elastic collision.
Index fossils (also known as guide
fossils, indicator fossils or zone
fossils) are fossils used to define
and identify geologic periods (or
faunal stages).
The triangle <span>in the first law of thermodynamics, represents energy that moves from a hot object to a cooler object.</span>
Answer: 
Explanation:
We know that force acting on an object due to Earth's gravity on the surface is given by:
where g is the acceleration due to gravity, r would be radius of Earth, M is the mass of Earth and G is the gravitational constant.
It is given that at pole, g = 9.830 m/s² and r = 6371 km = 6371 × 10³ m
Hence, Earth's mass is 
