Answer:

Explanation:
Given
,
,
,
The tension of the spring is



The force in the spring is equal to centripetal force so


But Fc is also
Fc=KxΔr

Replacing



total distance is

A.Momentum Equation
m = mass = 75 kg
v = velocity = 18 m/s
P = momentum
Using the momentum equation , momentum is given as
P = mv
P = 75 x 18
P = 1350 kgm/s
Answer:
Volume of balloon = 1000 cm^3
Explanation:
The head of a normal person can be assumed as a sphere with radius 10 cm.
Volume of sphere
, where r is the radius.
We have approximate radius = 10 cm.
Approximate volume of head 
In the given options the closest value to the approximate volume is 1000 cm^3.
So, volume of head = Volume of balloon = 1000 cm^3
Answer: An iron atom emits particles when it is struck by light (by the photoelectric effect)
Explanation:
The first atomic model was the one proposed by Jhon Dalton, according to which it is postulated that:
"Matter is made up of indivisible, indestructible and extremely small particles called atoms."
That is, <u>the atom is a solid and indivisible mass.
</u>
However, the fenomenom by which an iron atom emits particles when it is struck by light (known as the photoelectric effect) can not be explaind by this<u> indivisible atom</u> model.
To understand it better:
The <u>photoelectric effect</u> consists of the emission of electrons (electric current) that occurs when light falls on a metal surface under certain conditions.
This is possible by considering light as a stream of photons, where each of them has energy. <u>This energy is be able to pull an electron out of the crystalline lattice of the metal and communicate, in addition, a kinetic energy. </u>This means the atom is not indivisible, but it is a composition of different particles.
In fact, currently it is known that each atom is composed of a nucleus and one or more electrons attached to the nucleus, which is composed of one or more protons and typically a similar number of neutrons.