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quester [9]
3 years ago
12

You drop a rock from rest out of a window on the top floor of a building, 25.0 m above the ground. When the rock has fallen 4.90

m, your friend throws a second rock straight down from the same window. You notice that both rocks reach the ground at the exact same time. What was the initial velocity of the rock that your friend threw? (Assume upward is the positive direction and downward is negative. Indicate the direction with the sign of your answer.)
Physics
1 answer:
ryzh [129]3 years ago
3 0

Answer:13.86 m/s

Explanation:

Given

building height=25 m

another rock is thrown after first rock has fallen 4.90 m

time taken by first rock to cover 4.90 m

s=ut+\frac{gt^2}{2}

4.90=0+\frac{9.81\times t^2}{2}

t=1 s

time taken by first rock to reach at bottom

s=ut+\frac{gt^2}{2}

25=0+\frac{9.81\times t^2}{2}

t=2.25 sec

Now second rock will take 1 s less than first rock

time for second rock=1.25 s

s=ut+\frac{gt^2}{2}

25=u\times 1.25+\frac{9.81\times 1.25^2}{2}

u\times 1.25=25-\frac{9.81\times 1.25^2}{2}

u=13.86 m/s

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Find the wavelength in meters for a transverse mechanical wave with an amplitude of 10 cm and a radian frequency of 20π rad/s if
nydimaria [60]

Answer:

The wavelength of the wave is 20 m.

Explanation:

Given that,

Amplitude = 10 cm

Radial frequency \omega = 20\pi\ rad/s

Bulk modulus = 40 MPa

Density = 1000 kg/m³

We need to calculate the velocity of the wave in the medium

Using formula of velocity

v=\sqrt{\dfrac{k}{\rho}}

Put the value into the formula

v=\sqrt{\dfrac{40\times10^{6}}{10^3}}

v=200\ m/s

We need to calculate the wavelength

Using formula of wavelength

\lambda =\dfrac{v}{f}

\lambda=\dfrac{v\times2\pi}{\omega}

Put the value into the formula

\lambda=\dfrac{200\times2\pi}{20\pi}

\lambda=20\ m

Hence, The wavelength of the wave is 20 m.

5 0
3 years ago
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V125BC [204]
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e
​
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3 0
3 years ago
Nancys airplane trip took 4 hour. For one-fourth of that time, the airplane flew at a speed of 880 km/h, it flew at a speed of 6
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So for a minute lets ignore the 880 km/h. If it took 4 hours and she flew at 600 km/h 600*4=2400. Now lets Look at the 880 bit. If it took 4 hours and she where to fly at 880 it would've been 880*4=3520. Lets do 2400-600=1800, now we've got the 600 kmh bit done. Now lets see if you fly 880 km/h for one hour then you add 1800+880=2680. 

Remember to thank and rate people who help you!
4 0
3 years ago
I need help with this someone help me?
Brilliant_brown [7]
Graph A so answer B also why isn’t answer a with graph A and B with graph B etc like that’s just confusing lol
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__________ is the study of things continually moving or at rest.
bogdanovich [222]

Force

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so force is your answer see why b/c

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