Work Energy and Power - Result Question 53

56. Two spheres A and B of masses m1 and m2 respectively collide. A is at rest initially and B is moving with velocity v along x-axis. After collision B has a velocity v2 in a direction perpendicular to the original direction. The mass A moves after collision in the direction.

(a) Same as that of B

[2012]

(b) Opposite to that of B

(c) θ=tan1(1/2) to the x-axis

(d) θ=tan1(1/2) to the x-axis

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Answer:

Correct Answer: 56. (d)

Solution:

  1. (d)

[Before collision]

[After collision] According to law of conservation of linear momentum along x-axis, we get

m1(0)+m2v=m1vcosθ

cosθ=m2vm1v

Similarly, law of conservation of linear momentum along y-axis, we get

m1(0)+m2(0)=m1vsinθ+m2(v2)

sinθ=m2v2m1v

From equations, (i) and (ii),

tanθ=(m2v2mv)×(m1vm2v)=12

θ=tan1(12) to the x-axis.

Let A moves in the direction, which makes an angle θ with initial direction i.e.,

tanθ=vyvx=m2v2m1/m2v2m1

tanθ=12

θ=tan1(12) to the x-axis.



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