A particle of mass m is projected with velocity y making an angle of 45° with the horizontal. When the particle lands on the level ground the…
NEET UG 2008 — Physics Mechanics
2008mcqmedium
A particle of mass m is projected with velocity y making an angle of 45∘ with the horizontal. When the particle lands on the level ground the magnitude of the change in its momentum will be
Official previous-year question
Held on 30 Apr 2008 · Verified 9 Jul 2026.
Options
A
2mv
B
mv/2
C
mv2
D
zero
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Solution
Key Idea: Required momentum is the difference of final and initial momentum. The situation is shown in figure. Change in momentum, Δp∴=pf−pi=m(vf−vi)=m[(vcos45∘i^−vsin45∘j^)−(vcos45∘i^+vsin45∘j^)]=m[(2vi^−2vj^)−(2vi^+2vj^)]=−2mvj^[Δp]=2mv Alternative : The horizontal momentum does not change. The change in vertical momentum is mvsinθ−(−mvsinθ)=2mv21=2mv
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