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A proton is fired from very far away directly at a fixed particle with charge q = 1.82 ✕ 10−18 C. If the initial speed of the proton is 3.5
Question
A proton is fired from very far away directly at a fixed particle with charge q = 1.82 ✕ 10−18 C. If the initial speed of the proton is 3.5 ✕ 105 m/s, what is its distance of closest approach to the fixed particle? The mass of a proton is 1.67 ✕ 10−27 kg.
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Physics
4 years
2021-08-21T17:02:39+00:00
2021-08-21T17:02:39+00:00 1 Answers
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Answer:
r = 2.56 10⁻¹² m
Explanation:
For this exercise let’s use energy conservation
Starting point, proton too far
Em₀ = K = ½ m v²
Final point. When proton is stop
Emf = U = k q₁ q₂ / r
How energy is conserved
Em₀ = Emf
½ m v² = k q₁ q₂ / r
r = 2k q₁ q₂ / m v²
Let’s calculate
r = 2 8.99 10⁸ 1.6 10⁻¹⁹ 1.82 10⁻¹⁸ / (1.67 10⁻²⁷ (3.5 10⁵)² )
r = 2.56 10⁻¹² m