Physics · Forces and Motion
Work through this past-paper style MCQ, then read the full explanation. Practice more physics questions on mMCQ with adaptive practice and topic analytics.
In elastic collision, when a massive body collides with light body at conditions m1 >> m2 and v2 = 0 ms-1, then the change in velocity will be written as:
- A
v1’ ≈ −v1 ; v2’ ≈ v1
- B
v1’ ≈ v1 ; v2’ ≈ 0
- C
v1’ ≈ v1 ; v2’ ≈ 2v1
- D
v1’ ≈ −v1 ; v2’ ≈ 0
Explanation:
V1' = (m1 - 0/m1 + 0) v1 + (2(m2) (0)/0 +m2)
V1' = (m1 / m2) v1 + 0
V1' = v1 + 0
V1' = v1
V2' = (2m1v1 / m1) + (0 - m1 / m1 + 0) (0)
V2' = 2v1
Hence,
v1' = v1 and v2' = 2v1
This option suggests the massive body rebounds with a reversed velocity and the light body moves with the initial velocity of the massive body. This is not consistent with the conservation laws for this scenario.
This option implies that neither body changes velocity, which doesn't satisfy the condition of an elastic collision where momentum and energy are conserved and transferred between bodies.
In this scenario, the massive body continues with its initial velocity, and the light body gains a velocity twice that of the massive body’s initial velocity. This option is consistent with the conservation of momentum and energy in elastic collisions.
This option implies the massive body completely reverses its velocity while the light body remains stationary, which isn't possible in a perfectly elastic collision involving different masses.
Tagged under Physics · Forces and Motion · 2009