An object with a mass of $4 k g$ $4 kg$ is lying still on a surface and is compressing a horizontal spring by $\frac{7}{8} m$ $7/8 m$ . If the spring's constant is $16 \frac{k g}{s^{2}}$ $16 (kg)/s^2$ , what is the minimum value of the surface's coefficient of static friction?

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Answer 1 · 2016-04-28T12:55:03

$0.36$ $0.36$

The spring applies a force of $- k x = - 16 \times \frac{7}{8} N = - 14 N$ $-kx = -16xx7/8 N = -14 N$

Now the force of friction on the object = $μ m g = μ 4 \times 9.8 N$ $mumg = mu4xx9.8 N$

so, if it is not moving, net force on the body must be zero,

hence:

$μ 4 \times 9.8 = 14$ $mu4xx9.8 = 14$
$\Rightarrow μ = \frac{7}{19.6} \approx 0.36$ $=> mu = 7/19.6 ~~0.36$

An object with a mass of 4 kg4kg4 kg is lying still on a surface and is compressing a horizontal spring by 7/8 m78m7/8 m. If the spring's constant is 16 (kg)/s^216kgs216 (kg)/s^2, what is the minimum value of the surface's coefficient of static friction?