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Two bodies A and B having masses in the ratio of 3 : 1 posses the same kinetic energy. The ratio of linear

momentum of B to A is

(A) 1 : 3
(B) 3 : 1
(C) 1: √3
(D) √3 :1

User Degustaf
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1 Answer

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Final answer:

The ratio of linear momentum of body B to body A, given that both bodies have the same kinetic energy and mass ratio of 3:1, is 1:√3. This is because body B must have a higher velocity to have the same kinetic energy as the more massive body A.

Step-by-step explanation:

The student's question involves determining the ratio of linear momentum of two bodies with different masses but possessing the same kinetic energy. The linear momentum is a vector quantity that is the product of a system's mass and its velocity (option c). Using the given mass ratio of 3:1 and equal kinetic energies, we can say that body B must be moving faster than body A since it has less mass.

The kinetic energy (KE) for both bodies can be written as:

KE(A) = 0.5 * mass(A) * velocity(A)^2

KE(B) = 0.5 * mass(B) * velocity(B)^2

Because the kinetic energies are equal, we have:

mass(A) * velocity(A)^2 = mass(B) * velocity(B)^2

Substituting the mass ratio, we get:

(3 * mass(B)) * velocity(A)^2 = mass(B) * velocity(B)^2

This simplifies to:

velocity(B)^2 = 3 * velocity(A)^2

Thus:

velocity(B) = sqrt(3) * velocity(A)

To find the momentum ratio, we multiply mass by velocity for each body:

momentum(B) = mass(B) * velocity(B) = 1 * sqrt(3) * velocity(A)

momentum(A) = 3 * mass(B) * velocity(A)

The momentum ratio is then:

momentum(B) / momentum(A) = (sqrt(3) * velocity(A)) / (3 * velocity(A))

Which simplifies to:

momentum ratio = sqrt(3) / 3 = 1 / sqrt(3)

Therefore, the correct answer is (C) 1: √3.

User Abhishek Jangid
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