Answer:
(b) In ideal condition we neglect mass of spring but in real springs mass of spring adds another factor to its time period.
since we are adding a factor of mass to the system, and frequency being inversely proportional to squared root of mass, we can come to a general conclusion that it effectively reduces the natural frequency .
Explanation:
kindly check the attachment for explanation.
Answer: 4 x 106
That’s how you write forty million in scientific notation.
Answer:
Kinetic energy of diver at 90% of the distance to the water is 9000 J
Explanation:
Let d is the distance between the position of the diver and surface of the pool.
Initially, the diver is at rest and only have potential energy which is equal to 10000 J.
As the diver dives towards the pool, its potential energy is converting into kinetic energy due to law of conservation of energy, as total energy of the system remains same.
Energy before diving = Energy during diving
(Potential Energy + Kinetic Energy) = (Kinetic Energy + Potential Energy)
When the diver reaches 90% of the distance to the water, its kinetic energy
is 90% to its initial potential energy, as its initial kinetic is zero,i.e.,
K.E. = 
K.E. = 9000 J