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A 64.0 kg student runs down the sidewalk and jumps with a horizontal speed of 4.53 m/s onto a stationary skateboard. The student and skateboard move down the sidewalk with a speed of 2.63 m/s. Find the mass of the skateboard.

User Memory Of A Dream
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1 Answer

26 votes
26 votes

ANSWER


46.24\operatorname{kg}

Step-by-step explanation

Parameters given:

Mass of student, m = 64.0 kg

Initial velocity of student, u = 4.53 m/s

Initial velocity of skateboard, U = 0 m/s

Final velocity of student and skateboard, v = 2.63 m/s

To solve this problem, we have to apply the law of conservation of momentum which states that the total momentum of a system is constant.

This implies that:


mu+MU=mv+MV

The final velocity of the student and skateboard are equal. This implies that:


mu+MU=(m+M)v

where M = mass of skateboard

Substitute the given values into the equation and solve for M:


\begin{gathered} (64\cdot4.53)+(M\cdot0)=(64+M)\cdot2.63 \\ 289.92+0=(64+M)\cdot2.63 \\ \Rightarrow64+M=(289.92)/(2.63) \\ 64+M=110.24 \\ \Rightarrow M=110.24-64 \\ M=46.24\operatorname{kg} \end{gathered}

That is the mass of the skateboard.

User Molikh
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