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3 years ago

Calculate the kinetic energy of a 2.2 kg brick when it has a speed of 4.9 m/s.

2 answers:

8 0

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SVEN [57.7K]3 years ago

4 0

Answer:

Kinetic energy of the brick is 26.4 Joule

Explanation:

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On a hot summer day, 3.50 ✕ 106 J of heat transfer into a parked car takes place, increasing its temperature from 36.5°C to 44.4

anygoal [31]

Answer:

a) $\Delta s=443037.9747\ J.K^{-1}$

b) $\Delta s=31868131.8681\ J.K^{-1}$

Explanation:

Given:

amount of heat transfer occurred, $dQ=3.5\times 10^6\ J$

initial temperature of car, $T_i=36.5+273=309.5\ K$

final temperature of car, $T_f=44.4+273=317.4\ K$

We know that the change in entropy is given by:

$\Delta s=\frac{dQ}{T_f-T_i}$

$\Delta s=\frac{3.5\times 10^6}{(44.4-36.5)}$ (heat is transferred into the system of car)

$\Delta s=443037.9747\ J.K^{-1}$

amount of heat transfer form the system of house, $dQ=5.8\times 10^8\ J$

initial temperature of house, $T_i=23.5+273=296.5\ K$

final temperature of house, $T_f=5.3+273=278.3\ K$

$\Delta s=\frac{dQ}{T_f-T_i}$

$\Delta s=\frac{5.8\times 10^8}{278.3-296.5}$

$\Delta s=31868131.8681\ J.K^{-1}$

6 0

3 years ago

The temperature of the air in a valley begins to increase after the sun comes up and heats the valley floor. What will

tester [92]

Explanation:

I think it will increase a little bit ... just image ... if the temperature is 0, the velocity will be 0 too. because the vibration of atom is so weak and the sound cant progation.

7 0

3 years ago

Give reason for the following:

Zigmanuir [339]

a) An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. This is because a positive and negative electric charge is produced, therefore the balloon sticks to the wall.

b) When an object is thrown up, it comes back to ground because of gravitational attraction force of earth.

c) Mountaineers suffer nose bleeding at higher altitudes because the oxygen level decreases with increase in altitude, which the body cannot adjust.

d) Foundations of high rise buildings are kept wide because more is the area of contact, less is the pressure efforts. So, foundations are wide so as to decrease the possibility of the building from falling down.

e) Deep sea divers or high altitude fliers wear special suits so as prevent their body from being crushed by the water pressure. Since water pressure is maximum at deep seas and oceans, therefore, more is the risk of being injured.

f) Walls of a dam are thickened near the base so that the dam can handle the kinetic energy pressure and prevent itself from breaking down, which if not, can lead to flooding.

HOPE IT HELPS...

5 0

3 years ago

A man pushing a mop across a floor causes it to undergo two displacements. The first has a magnitude of 152 om and makes an angl

aliya0001 [1]

Answer:

D₂= 167,21 cm : Magnitude of the second displacement

β= 21.8° , countercockwise from the positive x-axis: Direction of the second displacement

Explanation:

We find the x-y components for the given vectors:

i: unit vector in x direction

j:unit vector in y direction

D₁: Displacement Vector 1

D₂: Displacement Vector 2

R= resulta displacement vector

D₁= 152*cos110°(i)+152*sin110°(j)=-51.99i+142.83j

D₂= -D₂(i)-D₂(j)

R= 131*cos38°(i)+ 131*sin38°(j) = 103.23i+80.65j

We propose the vector equation for sum of vectors:

D₁+ D₂= R

-51.99i+142.83j+D₂x(i)-D₂y(j) = 103.23i+80.65j

-51.99i+D₂x(i)=103.23i

D₂x=103.23+51.99=155.22 cm

+142.83j-D₂y(j) =+80.65j

D₂y=142.83-80.65=62.18 cm

Magnitude and direction of the second displacement

$D_{2} =\sqrt{(D_{x})^{2} +(D_{y} )^{2} }$

$D_{2} =\sqrt{(155.22)^{2} +(62.18 )^{2} }$

D₂= 167.21 cm

Direction of the second displacement

$\beta = tan^{-1} \frac{D_{y}}{D_{x} }$

$\beta = tan^{-1} \frac{62.18}{155.22 }$

β= 21.8°

D₂= 167,21 cm : Magnitude of the second displacement

β= 21.8.° , countercockwise from the positive x-axis: Direction of the second displacement

6 0

4 years ago

Diesel fuel is used in the engine of trucks that carry dirt fruit and other cargo. Fuel is burned in engines to make the motor m

Marina86 [1]

Answer: Fuel is burned in engines to make the motor move.

( Chemical to Mechanical )

Explanation:

during combustion of the diesel ( when the fuel is burnt in the engine of the vehicle, the diesel ( chemical energy ) is transformed or converted to Mechanical energy. This mechanical energy is what the truck uses in moving. Without the combustion of the fuel the vehicle won’t move and the combustion of diesel is achieved through compression unlike that of fuel.

4 0

3 years ago