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3 years ago

Choose the false statement regarding resistance.

Physics

1 answer:

Scilla [17]3 years ago

3 0

'A' is the false one, but 'C' is also so poorly worded that it's misleading.

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A soccer player kicks a rock horizontally off a 37 m high cliff into a pool of water. If the player hears the sound of the splas

Alchen [17]

<h2>Answer:</h2>

(a). 16.741 m/s

(b). 15.75 m/s

<h2>Explanation:</h2>

In the question,

Height of the cliff, h = 37 m

Time taken to reach the sound to us = 2.92 s

Speed of the sound in air at room temperature = 343 m/s

Now,

Let us say the speed of the ball = u m/s

So,

Time taken by the ball to reach at the bottom, t is given by,

$t=\sqrt{\frac{2h}{g}}\\t=\sqrt{\frac{2\times 37}{9.8}}\\t=2.747\,s$

So,

Splash is heard after = 2.92 s

So,

Time taken by sound to travel the shortest distance along the hypotenuse of the triangle thus formed is,

t = 2.92 - 2.747

t = 0.172 s

Now,

Distance traveled by sound is given by,

$Distance=343\times 0.172\\Distance=59.02\,m$

So,

In the triangle using the Pythagoras Theorem,

Horizontal distance traveled is,

$D=\sqrt{59.02^{2}-37^{2}}\\D=45.99\,m$

So,

Speed of throwing of ball is given by,

$Distance=Speed\times Time\\45.99=u\times 2.747\\u=16.741\,m/s$

Therefore, the speed of the ball = 16.741 m/s.

(b).

If,

Speed of sound = 331 m/s

So,

Distance traveled by sound is,

$Distance=331\times 0.172\\Distance=56.932\,m$

So,

Distance traveled in the horizontal by ball is,

$Distance=\sqrt{56.932^{2}-37^{2}}\\Distance=43.269\,m$

So,

Speed of the ball thrown is given by,

$Speed=\frac{Distance}{Time}\\Speed=\frac{43.269}{2.747}\\Speed=15.75\,m/s$

Therefore, the speed of the ball = 15.75 m/s.

8 0

3 years ago

A wheel of diameter 30.0 cm starts from rest and rotates with a constant angular acceleration of 3.50 rad/s2 . At the instant th

____ [38]

Answer: The radial acceleration of a point on the rim in two ways is 13.20 m/s^2

Explanation: Please see the attachments below

5 0

3 years ago

In a certain electrolysis experiment involving Al3+ ions, 60.2 g of Al is recovered when a current of 0.352 A is used. How many

yawa3891 [41]

Answer:

30.5 x 10³ min.

Explanation:

Atomic weight of aluminium = 27

For the reaction

Al⁺³ + 3e = Al

3 mole of electron is required by 1 mole of aluminium

3 x 96500 C of charge is required for 27 gram of aluminium

60.2 g aluminium will require

$\frac{3\times96500}{27} \times60.2$

645.47 x 10³ C

So charge required = 645.47 x 10³ C

Now Charge = Current x time

Current ( given ) = 0.352A

Time = charge / current = 645.47 x 10³ / .352

=1833 x 10³ s

30.5 x 10³ minutes

6 0

3 years ago

What is a central therapeutic technique of psychoanalysis?

finlep [7]

These techniques are central to psychoanalytic therapy. They can be used alone or in combination with one another. Their purpose is to increase awareness and foster insight into the client's behavior and emotions

please rate and thanks me if this helped

8 0

3 years ago

Why do you think glass bottles keep water cold longer?

Nina [5.8K]

Because glass is not a good heat conductor. What it means is that heat isn't transfered through its structure as quickly as it would with metal, for instance. Because heat can't penetrate glass as quickly, the contents stay at the same temperature for longer.

5 0

3 years ago