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3 years ago

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I need help on this!

1 answer:

sergij07 [2.7K]3 years ago

8 0

Try looking it up. that might help

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A mass of 150 g stretches a spring 1.568 cm. If the mass is set in motion from its equilibrium position with a downward velocity

nadezda [96]

Answer:

$u(t)=\frac{1}{5} sin\ (25t)$

Explanation:

Given:

mass of the body stretching the spring, $m=150\ g$

extension in spring, $\Delta x=1.568\ cm$

velocity of oscillation, $u'(0)=20\ cm.s^{-1}$

initial displacement position of equilibrium, $u(0)=0$

<u>According to given:</u>

$m.g=k.\Delta x$

$150\times 980=k\times 1.568$

$k=93750\ dyne.cm^{-1}$

<u>we know frequency:</u>

$\omega=\sqrt{\frac{k}{m} }$

$\omega=\sqrt{\frac{93750}{150} }$

$\omega=25$

Now, for position of mass in oscillation:

$u= A.sin\ (\omega.t)+B.cos\ (\omega.t)$

$u= A.sin\ (25.t)+B.cos\ (25.t)$

at $t=0;\ u(0)=0\ \Rightarrow A=0$

∴ $u(t)=B.sin\ (25.t)$

∵ at $t=0;\ u'(0)=20\ cm.s^{-1}\ \Rightarrow B=\frac{1}{5}$

$u(t)=\frac{1}{5} sin\ (25t)$

7 0

3 years ago

Nataly_w [17]

A is the answer i hope

5 0

4 years ago

I need help with question 8 and 9

Wewaii [24]

8) The height of the shelf is 2.04 m

9) The gravitational potential energy is 100 J

Explanation:

8)

The gravitational potential energy of an object is given by:

$PE=mgh$

where

m is the mass of the object

g is the acceleration of gravity

h is the heigth of the object, relative to the ground

For the object in this problem, we have

m = 10 kg

$g=9.8 m/s^2$

And we know that

PE = 200 J

Therefore we can re-arrange the formula to solve for h, the heigth of the object:

$h=\frac{PE}{mg}=\frac{200}{(10)(9.8)}=2.04 m$

9)

As before, the gravitational potential energy of the object is given by:

$PE=mgh$

where in this case, we have:

m = 10 kg is the mass of the object

h = 2.04 m is the height of the object from the ground

While in this case, the acceleration of gravity on this planet is

$g=4.9 m/s^2$

Substituting,

$PE=(10)(4.9)(2.04)=100 J$

Learn more about potential energy:

brainly.com/question/1198647

brainly.com/question/10770261

#LearnwithBrainly

7 0

4 years ago

Why is the temperature of the liquid in the flask on the previous page measured when the liquid in the thermometer has stopped r

Flura [38]

when heated, the molecules of the liquid in the thermometer move faster, causing them to get a little further apart. this results in movement up the thermometer. when cooled, the molecules of the liquid in the thermometer move slower, causing them to get a little closer together.

3 0

3 years ago

A sanding disk with rotational inertia 2.0 x 10-3 kg·m2 is attached to an electric drill whose motor delivers a torque of magnit

Inessa05 [86]

Answer

Given,

Rotational inertia = 2.0 x 10-3 kg·m²

Torque = 11 N.m

time, t = 19 ms

a) Angular momentum

$\tau = \dfrac{\Delta L}{\Delta t}$

L is angular momentum

$\Delta L = \tau \Delta t$

$\Delta L = 11\times 19 \times 10^{-3}$

$\Delta L = 0.209\ Kg m^2/s$

b) Angular velocity

We know.

$L = I \omega$

$\omega = \dfrac{L}{I}$

$\omega = \dfrac{0.209}{2\times 10^{-3}}$

$\omega = 104.5\ rad/s$

4 0

3 years ago