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2 years ago

5

How long does it take someone to run 8 miles if they are running at a speed of 7 km/hr?

1 answer:

ZanzabumX [31]2 years ago

7 0

Answer:

1.84 hours or 110.4 minutes

Explanation:

8 miles 1.61 km 1 hr

------------ x ----------------- x -------------- = 1.84 hours or 110.4 minutes

1 mile 7 km

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Susan's 12.0 kg baby brother Paul sits on a mat. Susan pulls the mat across the floor using a rope that is angled 30∘ above the

Pavlova-9 [17]

Answer:1.71 m/s

Explanation:

Given

mass of Susan $m=12 kg$

Inclination $\theta =30^{\circ}$

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$F_x=T\cos \theta -f_r$

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since there is no movement in Y direction therefore

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and $f_r=\mu N$

Thus $F_x=T\cos \theta -\mu N$

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$F_x=25.114-18.558$

$F_x=6.556 N$

Work done by applied Force is equal to change to kinetic Energy

$F_x\cdot x=\frac{1}{2}\cdot mv_f^2-\frac{1}{2}\cdot mv_i^2$

$6.556\times 2.7=\frac{1}{2}\cdot 12\times v_f^2$

$v_f^2=\frac{6.556\times 2.7\times 2}{12}$

$v_f^2=2.95$

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If two vectors are perpendicular to each other, how should you add them?

Aleksandr [31]

Let us consider two vectors A and B.

As per the question, the two vectors are perpendicular to each other.

Hence the angle between them $\theta =90 degree$

We are asked to calculate the resultant of these two vectors.

As per parallelogram law of vector addition, the resultant of two vectors are-

$R=\sqrt{A^{2}+ B^{2}+2ABcos\theta$

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