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3 years ago

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A glider has a mass m = 0.4 kg and is resting on a track that has a small but finite coefficient of kinetic friction. It is atta

ched to a spring with force constant k = 20 N/m. The relaxed position of the spring corresponds to x= 0. The glider is pulled out to x = 0.2 m and then released. If its speed is 1.0 m/s when it first reaches x = 0.1 m, determine the work done by friction during that segment of the motion.

1 answer:

Mariana [72]3 years ago

4 0

Answer:

-0.1 Joules

Explanation:

Here, the kinetic energy of the spring and glider is conserved.

So, we get

KE of spring + Work done by friction = Change in momentum of glider

$\frac{1}{2}k(x_f^2-x_i^2)+W_f=\frac{1}{2}m(v^2-u^2)\\\Rightarrow W_f=\frac{1}{2}m(v^2-u^2)-\frac{1}{2}k(x_f^2-x_i^2)\\\Rightarrow W_f=\frac{1}{2}0.4(1^2-0^2)-\frac{1}{2}20(0.2^2-0.1^2)\\\Rightarrow W_f=-0.1\ Joules$

The work done by friction during that segment of motion is -0.1 Joules

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