Answer:
time of collision is
t = 0.395 s

so they will collide at height of 5.63 m from ground
Explanation:
initial speed of the ball when it is dropped down is

similarly initial speed of the object which is projected by spring is given as

now relative velocity of object with respect to ball

now since we know that both are moving under gravity so their relative acceleration is ZERO and the relative distance between them is 6.4 m



Now the height attained by the object in the same time is given as



so they will collide at height of 5.63 m from ground
Answer:
The energies corresponding to each of the allowed orbitals are called energy levels.
Explanation:
A scientist known as Niels Bohr put forward that electrons in an atom covers some permitted orbitals with a specific energy. In other words, the energy of an electron in an atom is not continuous, but 'quantized.' The energies corresponding to each of the allowed orbitals are called energy levels.

Answer:
Choice A
Explanation:
The lower the point the higher the kinetic energy because Mechanical energy is conserved and the Gravitational Potential Energy gets lower when the height is lower
While falling, both the sheet of paper and the paper ball experience air resistance. But the surface area of the sheet is much more than that of the spherical ball. And air resistance varies directly with surface area. Hence the sheet experiences more air resistance than the ball and it falls more slowly than the paper ball.
Hope that helps!