If A=

Where will you find the most kinetic energy? ice or water?

const2013 [10]

Answer:

Water has more kinetic energy because it is liquid, as ice is harder, so it's cells can't move as much.

7 0

3 years ago

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A baseball is thrown at an angle of 25 degrees relative to the ground at a speed of 23 m/s. If the ball was caught 42 m from the

ExtremeBDS [4]

Answer:

a) $v_{0y} = 9.72 m/s$

b) $v_{0x} = 20.85 m/s$

c) $t = 2.01 s$

d) $h_{max} = 4.82 m$

Explanation:

a) The initial vertical velocity is given by:

$v_{0y} = v*sin(\theta)$

Where:

θ: 25°

v: is the magnitude of the speed = 23 m/s

$v_{0y} = 23 m/s*sin(25) = 9.72 m/s$

b) The initial horizontal velocity can be calculated as follows:

$v_{0x} = v*cos(\theta) = 23 m/s*cos(25) = 20.85 m/s$

c) The flight time can be calculated using the following equation:

$v_{0x} = \frac{x}{t}$

Where:

x: is the total distance = 42 m

$t = \frac{x}{v_{0x}} = \frac{42 m}{20.85 m/s} = 2.01 s$

d) The maximum height is given by:

$v_{fy}^{2} = v_{0y}^{2} - 2gh_{max}$

Where:

$v_{fy}$ : is the final vertical velocity =0 (at the maximum heigth)

g: is the gravity = 9.81 m/s²

$h_{max} = \frac{v_{0y}^{2}}{2g} = \frac{(9.72 m/s)^{2}}{2*9.81 m/s^{2}} = 4.82 m$

I hope it helps you!

7 0

3 years ago

Water evaporating from a pond does so as if it were diffusing across an air film 0.15 cm thick. The diffusion coefficient of wat

QveST [7]

Answer:

The water level will drop by about 1.24 cm in 1 day.

Explanation:

Here Mass flux of water vapour is given as

$j_{H_2O}=\frac{D}{l} \bigtriangleup c$

where

$j_{H_2O}$ is the mass flux of the water which is to be calculated.

D is diffusion coefficient which is given as $0.25 cm^2/s$

l is the thickness of the film which is 0.15 cm thick.
$\bigtriangleup c$ is given as

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT}$

In this

$P_{sat}$ is the saturated water pressure, which is look up from the saturated water property at 20°C and 0.5 saturation given as 2.34 Pa

$P_a$ is the air pressure which is given as 0.5 times of $P_{sat}$

R is the universal gas constant as $8.314 kJ/kmol-K$

T is the temperature in Kelvin scale which is $20+273= 293K$

By substituting values in the equation

$\bigtriangleup c= \frac{P_{sat}-P_a}{RT} \\ \bigtriangleup c= \frac{P_{sat}-0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5P_{sat}}{RT} \\ \bigtriangleup c= \frac{0.5 \times 2.34}{8.314 \times 293} \\\bigtriangleup c= 0.48 mol/m^3$

Converting $\bigtriangleup c$ into $cm^3/cm^3$

As 1 mole of water 18 $cm^3$ so

$\bigtriangleup c= 0.48 mol/m^3 \\ \bigtriangleup c= 0.48 \times 18 \times 10^{-6} cm^3/cm^3 \\ \bigtriangleup c= 8.64 \times 10^{-6} cm^3/cm^3$

Putting this in the equation of mass flux equation gives

$j_{H_2O}=\frac{D}{l} \bigtriangleup c \\ j_{H_2O}=\frac{0.25}{0.15} \times 8.64 \times 10^{-6} \\ j_{H_2O}=14.4 \times 10^{-6} cm/s$

For calculation of water level drop in a day, converting mass flux as

$j_{H_2O}=14.4 \times 10^{-6} \times 24 \times 3600 cm/day\\ j_{H_2O}=1.24 cm/day$

So the water level will drop by about 1.24 cm in 1 day.

7 0

4 years ago

Find the sum. Express the answer in scientific notation.<br> (1.54 x 10^6)+(6.15 x 10°)

klasskru [66]

ans will be 1500006.15

= 1.5*10^6

we move the decimal point to the left six digits

8 0

3 years ago

Which one of the following types of electromagnetic radiation causes certain substances to fluoresce?

ioda

From the choices given, ultraviolet rays is a type electromagnetic radiation that causes certain substances to fluoresce. It cannot be detected by the naked eye but some insects are able to see them.

Like in a fluorescent light bulb, ultraviolet or UV lights stimulates the coating of the tube to emit light.

5 0

4 years ago