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2 years ago

What is the work required to lift a 10 kg box off the ground to a height of 5.0 m?

Physics

1 answer:

FinnZ [79.3K]2 years ago

7 0

Answer:

490J

Explanation:

Given parameters:

Mass of box = 10kg

Height = 5m

Unknown:

Work done = ?

Solution:

Work done can be derived from the product of force and distance;

Work done = force x distance

Force here is applied by gravity and it is the weight

The distance is the height

Work done = weight x height

Work done = mass x acceleration due to gravity x height

Work done = 10 x 9.8 x 5 = 490J

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Answer:

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Explanation:

It is given that, a small metal ball is suspended from the ceiling by a thread of negligible mass. The ball is then set in motion in a horizontal circle so that the thread’s trajectory describes a cone as shown in attached figure.

From the figure,

The sum of forces in y direction is :

$T\ cos\theta-mg=0$

$T=\dfrac{mg}{cos\theta}$

Sum of forces in x direction,

$T\ sin\theta=\dfrac{mv^2}{r}$

$mg\ tan\theta=\dfrac{mv^2}{r}$ .............(1)

Also, $r=l\ sin\theta$

Equation (1) becomes :

$mg\ tan\theta=\dfrac{mv^2}{l\ sin\theta}$

$v=\sqrt{gl\ tan\theta.sin\theta}$ ...............(2)

Let t is the time taken for the ball to rotate once around the axis. It is given by :

$T=\dfrac{2\pi r}{v}$

Put the value of T from equation (2) to the above expression:

$T=\dfrac{2\pi r}{\sqrt{gl\ tan\theta.sin\theta}}$

$T=\dfrac{2\pi l\ sin\theta}{\sqrt{gl\ tan\theta.sin\theta}}$

On solving above equation :

$T=2\pi \sqrt{\dfrac{l\ cos\theta}{g}}$

Hence, this is the required solution.

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A small cart travels 20 meters to the right in 10 seconds calculate the velocity

stira [4]

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fredd [130]

Answer:

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Explanation:

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It is required to find the frequency of the radio waves. The speed of a wave is given by :

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diamong [38]

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3 years ago

A ball is connected to a light spring suspended vertically. When pulled downward from its equilibrium position and released, the

babunello [35]

Answer:

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