Answer:
486 of cell membranes
Explanation:
one cell membrane has 7*10^-9m as the height
So, by dividing 3.4 with 7*10^-9 you will get the number of cell require to form the height.
3.4/(7*10^-9)=485.71
because we can't have decimal number of cell we would round it into three significant figures, 486.
Via the half-life equation:

Where the time elapse is 11,460 year and the half-life is 5,730 years.

Therefore after 11,460 years the amount of carbon-14 is one fourth (1/4) of the original amount.
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
Answer:270joules
Explanation:KE = 1/2mv^2
KE = 1/2(60kg)(3.0)^2 = 270 Joules
Decrease because its 0.0 m/s