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2 years ago

6

While rearranging a dorm room, a student does 310 J of work in moving a desk 2.9 m. What was the magnitude of the applied horizo

ntal force?

1 answer:

Viefleur [7K]2 years ago

3 0

Answer:

The horizontal force is 106.89 N.

Explanation:

Given that,

Work done = 310 J

Distance = 2.9 m

We need to calculate the horizontal force

Using formula of work done

$W= Fd\cos\theta$

Where, $\theta=0^{\circ}$

$W=F\cdot d$

Put the value into the formula

$310=F\cdot 2.9$

$F=\dfrac{310}{2.9}$

$F=106.89\ N$

Hence, The horizontal force is 106.89 N.

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A 1400-kg car is moving at a speed of 25m/s. how much kinetic energy does the car have?

Luba_88 [7]

Answer:

437.5Kjoules

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2 years ago

How many revolutions per minute would a 23 m -diameter Ferris wheel need to make for the passengers to feel "weightless" at the

kirza4 [7]

Answer:

Approximately $6.2\; {\rm rpm}$ , assuming that the gravitational field strength is $g = 9.81\; {\rm m\cdot s^{-2}}$ .

Explanation:

Let $\omega$ denote the required angular velocity of this Ferris wheel. Let $m$ denote the mass of a particular passenger on this Ferris wheel.

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This passenger would feel "weightless" if the normal force on them is $0$ - that is, $F_\text{normal} = 0$ .

The net force on this passenger is $(m\, g - F_\text{normal})$ . Hence, when $F_\text{normal} = 0$ , the net force on this passenger would be equal to $m\, g$ .

Passengers on this Ferris wheel are in a centripetal motion of angular velocity $\omega$ around a circle of radius $r$ . Thus, the centripetal acceleration of these passengers would be $a = \omega^{2}\, r$ . The net force on a passenger of mass $m$ would be $m\, a = m\, \omega^{2}\, r$ .

Notice that $m\, \omega^{2} \, r = (\text{Net Force}) = m\, g$ . Solve this equation for $\omega$ , the angular speed of this Ferris wheel. Since $g = 9.81\; {\rm m\cdot s^{-2}}$ and $r = 23\; {\rm m}$ :

$\begin{aligned} \omega^{2} = \frac{g}{r}\end{aligned}$ .

$\begin{aligned} \omega &= \sqrt{\frac{g}{r}} \\ &= \sqrt{\frac{9.81\; {\rm m \cdot s^{-2}}}{23\; {\rm m}}} \\ &\approx 0.653\; {\rm rad \cdot s^{-1}} \end{aligned}$ .

The question is asking for the angular velocity of this Ferris wheel in the unit ${\rm rpm}$ , where $1\; {\rm rpm} = (2\, \pi\; {\rm rad}) / (60\; {\rm s})$ . Apply unit conversion:

$\begin{aligned} \omega &\approx 0.653\; {\rm rad \cdot s^{-1}} \\ &= 0.653\; {\rm rad \cdot s^{-1}} \times \frac{1\; {\rm rpm}}{(2\, \pi\; {\rm rad}) / (60\; {\rm s})} \\ &= 0.653\; {\rm rad \cdot s^{-1} \times \frac{60\; {\rm s}}{2\, \pi\; {\rm rad}} \times 1\; {\rm rpm} \\ &\approx 6.2\; {\rm rpm} \end{aligned}$ .

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1 year ago

A drum is struck first with little energy. The drum is then struck with a lot of energy. Which sound will be louder? Why?

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Answer:

The drum struck with a lot of energy would be louder than the drum struck with little energy because there is a harder impact on it

Explanation:

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2 years ago

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2 years ago

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The complete question is;

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Answer:

Water becomes warmer by a temperature of ΔT = 0.119 K

Explanation:

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