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3 years ago

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A block with initial velocity of 3 m/s slides 9 m across a rough horizontal surface before coming to rest. What is the coefficie

nt of kinetic
friction?

1 answer:

Yakvenalex [24]3 years ago

6 0

The coefficient of kinetic friction between the block and the horizontal surface is 0.051.

The given parameters;

<em>initial velocity, u = 3 m/s</em>
<em>distance traveled by the block, s = 9 m</em>

The acceleration of the block is calculated as follows;

$v^2 = u^2 + 2(-a)s\\\\v^2 = u^2 - 2as\\\\a = \frac{u^2 - v^2}{2s} \\\\a = \frac{3^2 - 0^2}{2\times 9} \\\\a =0.5 \ m/s^2$

The coefficient of kinetic friction between the block and the horizontal surface is calculated as follows;

$\mu_k mg = ma\\\\\mu_k = \frac{a}{g} \\\\\mu_k = \frac{0.5}{9.8} \\\\\mu_k = 0.051$

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Two workers are sliding 300 kg crate across the floor. One worker pushes forward on the crate with a force of 400 N while the ot

almond37 [142]

Answer:

The kinetic coefficient of friction of the crate is 0.235.

Explanation:

As a first step, we need to construct a free body diagram for the crate, which is included below as attachment. Let supposed that forces exerted on the crate by both workers are in the positive direction. According to the Newton's First Law, a body is unable to change its state of motion when it is at rest or moves uniformly (at constant velocity). In consequence, magnitud of friction force must be equal to the sum of the two external forces. The equations of equilibrium of the crate are:

$\Sigma F_{x} = P+T-\mu_{k}\cdot N = 0$ (Ec. 1)

$\Sigma F_{y} = N - W = 0$ (Ec. 2)

Where:

$P$ - Pushing force, measured in newtons.

$T$ - Tension, measured in newtons.

$\mu_{k}$ - Coefficient of kinetic friction, dimensionless.

$N$ - Normal force, measured in newtons.

$W$ - Weight of the crate, measured in newtons.

The system of equations is now reduced by algebraic means:

$P+T -\mu_{k}\cdot W = 0$

And we finally clear the coefficient of kinetic friction and apply the definition of weight:

$\mu_{k} =\frac{P+T}{m\cdot g}$

If we know that $P = 400\,N$ , $T = 290\,N$ , $m = 300\,kg$ and $g = 9.807\,\frac{m}{s^{2}}$ , then:

$\mu_{k} = \frac{400\,N+290\,N}{(300\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)}$

$\mu_{k} = 0.235$

The kinetic coefficient of friction of the crate is 0.235.

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During spring tide, the sun, earth, and moon are in a straight line. This causes ...............

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Answer:

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A 0.954-kg toy car is powered by three D cells (4.50 V total) connected directly to a small DC motor. The car has an effective e

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Answer:

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Explanation:

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so input to the motor = output/efficiency

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Answer:

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Explanation:

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<em>For the males, the length of the femur in centimeters is multiplied by 2.32 followed by the addition of 65.53 in order to arrive at the approximate height of the individual. For the females, on the other hand, the length of the femur in centimeters is multiplied by 2.47 followed by the addition of 54.1.</em>

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A wire of length L is wound into a square coil with 167 turns and used in a generator that operates at 60.0 Hz and 120 V rms val

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Answer:

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The peak emf is:

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Substituting $w=2\pi f$ and the value for peaf $E$ gives:

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= $171.43m$

Hence, wire's length is 171.43m

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