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3 years ago

A 120 g coconut falls 12 m. What is the kinetic energy of the coconut just before it hits the ground?

1 answer:

5 0

Kinetic Energy (Ek) =
$m \times {v}^{2} \div 2$

Torricelli's Equation
g earth = 10m/s^2

${v}^{2} = {vo}^{2} + 2g \times delta(s) \\ {v}^{2} = 0 + 2 \times 10 \times 12 \\ {v}^{2} = 240m/s$

120g = 0.12 kg

Ek = 0.12 x 240/2
Ek = 28.8/2
Ek = 14.4 J

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How many values must a 1-D<br> motion problem give you in<br> order to solve it?

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Answer:

I think it is B: 3

Explanation:

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3 years ago

Water is boiled at sea level in a coffeemaker equipped with an immersion-type electric heating element. The coffee maker contain

Luden [163]

Answer:

$P=1362\ W$

$t'=251.659\ s$ is time required to heat to boiling point form initial temperature.

Explanation:

Given:

initial temperature of water, $T_i=18^{\circ}C$

time taken to vapourize half a liter of water, $t=18\ min=1080\ s$

desity of water, $\rho=1\ kg.L^{-1}$

So, the givne mass of water, $m=1\ kg$

enthalpy of vaporization of water, $h_{fg}=2256.4\times 10^{-3}\ J.kg^{-1}$

specific heat of water, $c=4180\ J.kg^{-1}.K^{-1}$

Amount of heat required to raise the temperature of given water mass to 100°C:

$Q_s=m.c.\Delta T$

$Q_s=1\times 4180\times (100-18)$

$Q_s=342760\ J$

Now the amount of heat required to vaporize 0.5 kg of water:

$Q_v=m'\times h_{fg}$

where:

$m'=0.5\ kg=$ mass of water vaporized due to boiling

$Q_v=0.5\times 2256.4$

$Q_v=1.1282\times 10^{6}\ J$

Now the power rating of the boiler:

$P=\frac{Q_s+Q_v}{t}$

$P=\frac{342760+1128200}{1080}$

$P=1362\ W$

Now the time required to heat to boiling point form initial temperature:

$t'=\frac{Q_s}{P}$

$t'=\frac{342760}{1362}$

$t'=251.659\ s$

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4 years ago

A 5cm tall object is placed 4cm in front of a converging lens that has a focal length of 8cm. Where is the image located in ____

OverLord2011 [107]

Answer:

a. -8 cm

Explanation:

$d_{o}$ = distance of the object = 4 cm

$d_{i}$ = distance of the image = ?

$f$ = focal length of the converging lens = 8 cm

using the lens equation

$\frac{1}{d_{o}} + \frac{1}{d_{i}} = \frac{1}{f}$

$\frac{1}{4} + \frac{1}{d_{i}} = \frac{1}{8}$

$d_{i}$ = - 8 cm

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3 years ago

Which cells or organs are considered to be part of both the immune and lymphatic systems? Select all that apply.

Leviafan [203]

Answer:

lymph nodes

tonsils and adenoids

thymus

Explanation:

-Arteries are the blood vessels that take the blood that contains oxygen from the heart to the tissues and are part of the circulatory system.

-Lymph nodes are glands that take care of filtering the fluid that goes through the lympathic system and are also important for the functioning of the immune system.

-Capillaries are blood vessels that connect the veins and arteries and are part of the circulatory system.

-Tonsils and adenoids are located in the throat and they help protect the body from diseases and they are part of immune system and the lympathic system.

-Veins are the vessels that take the blood to the heart and they are part of the circulatory system.

-Thymus is an organ in which the T cells develop and they help protect the body against virus and bacteria and it is part of the immune and lympathic systems.

According to this, cells or organs that are considered to be part of both the immune and lymphatic systems are:

lymph nodes

tonsils and adenoids

thymus

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Westkost [7]

Answer:

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