The thickness of aluminium needed to stop the beam electrons, protons and alpha particles at the given dfferent kinetic energies is 1.5 x 10⁻¹⁴ m.
<h3>
Thickness of the aluminum</h3>
The thickness of the aluminum can be determined using from distance of closest approach of the particle.

where;
- Z is the atomic number of aluminium = 13
- e is charge
- r is distance of closest approach = thickness of aluminium
- k is Coulomb's constant = 9 x 10⁹ Nm²/C²
<h3>For 2.5 MeV electrons</h3>

<h3>For 2.5 MeV protons</h3>
Since the magnitude of charge of electron and proton is the same, at equal kinetic energy, the thickness will be same. r = 1.5 x 10⁻¹⁴ m.
<h3>For 10 MeV alpha-particles</h3>
Charge of alpah particle = 2e

Thus, the thickness of aluminium needed to stop the beam electrons, protons and alpha particles at the given dfferent kinetic energies is 1.5 x 10⁻¹⁴ m.
Learn more about closest distance of approach here: brainly.com/question/6426420
Answer:
Mechanical property
Explanation:
MECHANICAL PROPERTIES can be defined as the ability of a metal or material to remain undamaged after different type of forces has been applied or used on them because forces or loads are often applied to metal, material or physical properties which is why MECHANICAL PROPERTIES enables us to know the strength , toughness as well as the hardness of metal and the way this metal perform or react when different forces are applied on them.
Lastly any metal, material or physical properties that has the strength , hardness and resistance to withstand or remain unaffected despite the loads or forces use on them is an example of MECHANICAL PROPERTIES.
Therefore Resistance to impact is an example of a(n) MECHANICAL PROPERTIES.