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mixer [17]
3 years ago
6

A car moving with a velocity of 20 meters/second has

Physics
1 answer:
kenny6666 [7]3 years ago
5 0
Kinetic energy is the energy of an object in motion. It is expressed as the product of its mass and the square of its velocity. The opposite of this energy is called the potential energy, the energy of an object at rest. Calculations are as follows:
<span>
KE = mv^2
</span><span>1.8x10^5 J = m(20 m/s)^2
</span><span>m = 450 kg</span>
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A block of ice (m = 9 kg) at a temperature of T1 = 0 degrees C is placed out in the sun until it melts, and the temperature of t
jonny [76]

Answer:

a) An expression for the amount of energy, E_m, needed to melt the ice into water.

(E_m) = (m × Lf)

b) An expression for the total amount of energy, E_tot, to melt the ice and then bring the water to T2

(Total heat) = (m × Lf) + mc (T2 - T1)

c) 3,646,458 J = 3646.46 kJ

Explanation:

a) When a pure body changes its phase at meltimgbor boiling point, it does so at a constant temperature. When a pure body melts, the amount of heat responsible for this change is just given by a product od the mass of the body and the body's heat of fusion.

(E_m) = (m × Lf)

b) The Heat required to raise the temperature of a body from one temperature to another is given by the product of the mass of the body, its specific heat capacity and the temperature difference between the final point and the starting point.

(E_2) = mcΔT = mc (T2 - T1)

Total heat required to melt the ice at T1 = 0 and raise the temperature of the resulting water to T2 is then a sum of (E_m) + (E_2)

(Total heat) = (m × Lf) + mc (T2 - T1)

c) What is the energy in Joules?

(Total heat) = (m × Lf) + mc (T2 - T1)

m = mass of ice = resulting mass of water = 9 kg

Lf = latent heat of fusion = 334000 J/kg

c = Specific heat capacity of water = 4186 J/kg.K

T2 = final temperature of the water = 17°C

T1 = Initial temperature of the water = 0°C

Note that the units of temperature difference is the same for K and °C

(Total heat) = (m × Lf) + mc (T2 - T1)

Q = (9 × 334000) + [9 × 4186 × (17 - 0)]

Q = 3,006,000 + 640,458 = 3,646,458 J = 3646.46 kJ

Hope this Helps!!!

7 0
3 years ago
If you act without reason or sound judgement, people will describe you as __________.
EastWind [94]

Answer:

irrational

Explanation:

8 0
2 years ago
Density=2g/mL and volume=20mL what is mass
leva [86]

Answer:

40g

Explanation:

Mass = density x volume

= 2 x 20

= 40g

8 0
3 years ago
Read 2 more answers
A proton, which is the nucleus of a hydrogen atom, can be modeled as a sphere with a diameter of 2.4 fm and a mass of 1.67 10-27
Step2247 [10]
For the answer to the question above asking to d<span>etermine the density of the proton. 
</span>Density is mass over volume. 

The volume of a sphere is 4πr³/3. r is half the diameter. 

So the density would be 2.3×10¹⁷ kg/m³. 
I hope my answer helped you. Feel free to ask more questions. Have a nice day!
8 0
3 years ago
Read 2 more answers
An astronaut lands on an alien planet. He places a pendulum (L = 0.200 m) on the surface and sets it in simple harmonic motion,
Ne4ueva [31]
A)  f = 1.8 rev/s = 2 Hz 
<span>T = 1 / f = 0.55s

B)  not really sure..srry

C)  </span><span>T = 2 pi √ ( L / g ) </span>
<span>0.57 = 2 x 3.14 x √ ( 0.2 / g )
</span><span>
g = 25.5 m/s²
</span>
Hope this helps a little at least.. :)

5 0
3 years ago
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