A blob of material in outer space moves at 3 m/s when it collides and sticks to a half-as-massive blob initially at rest.Compared with the initial kinetic energy of the 3-m/s blob,the kinetic energy of the coupled blobs is

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Quizplus · Accepted Answer

The initial kinetic energy of the first blob can be evaluated as K1 = 0.5mv1^2, where m is the mass and v1 is the velocity of the first blob. The kinetic energy of the second blob before the collision is zero since it is initially at rest. After the collision, the two blobs stick together and move at the same velocity. We can use conservation of momentum to determine the final velocity of the coupled blobs as m1v1 = (m1 + m2)v_final. Rearranging and substituting the given values, we have v_final = m1v1/(m1 + m2) = 2/3 * v1. Thus, the kinetic energy of the coupled blobs after the collision is K_final = 0.5(m1 + m2) * v_final^2 = 0.5(m1 + m2) * (2/3*v1)^2 = 2/3 * K1. Therefore, the answer is B) two-thirds.

A Blob of Material in Outer Space Moves at 3