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2 years ago

11

A ball is dropped from a height h and falls the last half of its distance in 4 seconds. How long does the ball fall? From what h

eight is the ball originally dropped?

1 answer:

dlinn [17]2 years ago

8 0

Answer:

How long does the ball fall is t_2 = 13.66 (s).

From what height is the ball originally dropped is h= 913.90 (m).

Explanation:

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Sophie throws a tennis ball down from a height of 1.5 m at an angle of 450 with respect to vertical. She drops another tennis ba

Katena32 [7]

Given that,

Height =1.5 m

Angle = 45°

We need to find the greater speed of the ball

Using conservation of energy

$P.E_{i}+K.E_{f}=P.E_{f}+K.E_{f}$

$mgh+\dfrac{1}{2}mv_{i}^2=mgh+\dfrac{1}{2}mv_{f}^2$

Here, initial velocity and final potential energy is zero.

$mgh=\dfrac{1}{2}mv_{f}^2$

Put the value into the formula

$9.8\times1.5=\dfrac{1}{2}v_{f}^2$

$v_{f}^2=2\times9.8\times1.5$

$v_{f}=\sqrt{2\times9.8\times1.5}$

$v_{f}=5.42\ m/s$

Hence, the greater speed of the ball is 5.42 m/s.

5 0

2 years ago

Four traveling waves are described by the following equations, where all quantities are measured in SI units and y represents th

agasfer [191]

Answer:

$T_1=T_3=\dfrac{2\pi}{21}$

$T_2=T_4=\dfrac{2\pi}{42}$

Explanation:

Wave 1, $y_1=0.12\ cos(3x-21t)$

Wave 2, $y_2=0.15\ sin(6x+42t)$

Wave 3, $y_3=0.13\ cos(6x+21t)$

Wave 4, $y_4=-0.27\ sin(3x-42t)$

The general equation of travelling wave is given by :

$y=A\ cos(kx\pm \omega t)$

The value of $\omega$ will remain the same if we take phase difference into account.

For first wave,

$\omega_1=21$

$\dfrac{2\pi }{T_1}=21$

$T_1=\dfrac{2\pi}{21}$

For second wave,

$\omega_2=42$

$\dfrac{2\pi }{T_2}=42$

$T_2=\dfrac{2\pi}{42}$

For the third wave,

$\omega_3=21$

$\dfrac{2\pi }{T_3}=21$

$T_3=\dfrac{2\pi}{21}$

For the fourth wave,

$\omega_4=42$

$\dfrac{2\pi }{T_4}=42$

$T_4=\dfrac{2\pi}{42}$

It is clear from above calculations that waves 1 and 3 have same time period. Also, wave 2 and 4 have same time period. Hence, this is the required solution.

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3 years ago

An ionic compound is not represented by a molecular formula because an ionic compound is

Elenna [48]

Answer:

lacks molecules

Explanation:

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2 years ago

Inga [223]

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6 0

2 years ago

Read 2 more answers

As water runs over a waterfall, its potential energy is converted to _______________ energy.

kvasek [131]

It is converted into kinetic energy

6 0

2 years ago