You have designed a cheap version of a \"radar gun\", a way of measuring the vel

Question

You have designed a cheap version of a "radar gun", a way of measuring the velocity with which someone can throw a baseball. In your design, the baseball is thrown (horizontally) into a box full of a soft gel, so that the baseball embeds itself in the gel and sticks. The box and baseball then slide across a surface until they are stopped by friction. In your design, the mass of the box and putty is M = 1.84 kg, and the coefficient of kinetic friction between the box and the surface it's resting on is k = 0.21. The mass of a baseball is MBB = 0.145 kg. If the box and baseball slide a distance d = 1.00 m before stopping, what is the speed of the baseball when it hits the box? Give you answer in m/s to three significant digits. You will not be graded on the number of digits, this is just be be sure your answer is not counted as incorrect due to rounding. Do not include units in your answer.

Explanation / Answer

when box moves at rought surface,

a = - uk g = - 0.21 x 9.8

a = - 2.06 m/s^2

Applyng vf^2 - vi^2 =2 a d

0^2 - v^2 = 2 x - 2.06 x 1

v = 2.03 m/s ....THis is the speed of box plus baseball after collision.

Applying momentum conservation for the colliison,

0.145u + 1.84 x 0 = (1.84 + 0.145) x 2.03

u = 4.027 / 0.145

u = 27.8 m/s .........Ans

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