<h3><u>Answer;</u></h3>
<em>-Rubidium (Rb)</em>
<h3><u>Explanation;</u></h3>
- <em><u>Alkali metals are group 1 elements, </u></em>they have a valency of 1 and react by loosing electrons to attain a stable configuration.
- <em><u>The reactivity of alkali metals increases down the group, this is due to the increase in the number of energy levels</u></em> which makes it easier for the valence electrons to be lost.
- Therefore, in our case,<em><u> rubidium will be the most reactive as it contains more number of energy levels</u></em>, therefore it will loose valence electron more easily compared to the other alkali metals above it in the group.
Answer:
a) 3.6 N.s
b) 36 J
Explanation:
Given:
The mass of ball, m = 0.06 kg
The initial velocity v₁ = -20 m/s
final velocity v₂ = 40 m/s
Now,
The impulse is given as:
I= change in momentum
or
I = m( v₂ - v₁)
or
I = 0.06 × (40 - (-20))
or
I = 3.6 N.s
(b) work done = change in kinetic energy
W.D = ΔK.E
W.D =
on substituting the values
W.D =
W.D = 36 J
<span>Both objects receive the same impulse.</span>
Answer:
It is used in MRI because it does not damage cells
Radio waves are used for space research because they have very long wavelengths
Explanation:
Many parts of the electromagnetic spectrum are applied in clinical diagnosis and treatment of illnesses. However, these highly ionizing radiation damage cells and its dosage must be carefully managed to avoid creating radiation related health problems for the patients.
Radio waves can be used in MRI without issues because the energy of the radiation is not sufficient to cause damage to cells but is sufficient to provide images for the sake of medical diagnosis.
Secondly, radio waves have long wavelength. This property is suitable for long range
communication. Hence it can be used in space research
2) acceleration = final velocity - initial velocity / time —> V-U/T
Acceleration is the change in velocity over the change in time so it can be represented by the equation a = Δv/Δt.
3) first one- F=10.5 N
second one- 4 m/s^2
third one- 1200N