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4 years ago

How much heat energy in megajoules is needed to convert 7 kilograms of ice at -9c to water at 0c

Physics

2 answers:

gayaneshka [121]4 years ago

7 0

We can solve this by using the formulas provided to us by calorimetry.

The energy (heat) that is needed to change a given mass of some solid into its liquid form is

E=Lm·m (Where Lm is a specific constant for the material/substance and m is the mass)

Lm for solid water (i.e. ice) is 334 $\frac{Kj}{Kg}$

We can now solve for E

E= 334⋅2 Kj =668Kj

This is the minimum energy required to melt 2 kg of ice. Remember that this energy will in no way change the temperature of the water since every amount of this energy is needed just to melt the solid itself. Even more energy would be needed to increase the end temperature.

Musya8 [376]4 years ago

6 0

The latent heat of fusion of water is 344 j/p.This will take 344x300 or 100200 J to melt the ice. once it melted its at oc

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A dock worker loading crates on a ship finds that a 27 kg crate, initially at rest on a horizontal surface, requires a 80 N hori

Aleksandr-060686 [28]

Answer:0.302

Explanation:

Given

mass of crate m=27 kg

Force required to set crate in motion is 80 N

Once the crate is set in motion 56 N is require to move it with constant velocity

i.e. 80 N is the amount of force needed to just overcome static friction and 56 is the kinetic friction force

thus

$f_s(static\ friction)=\mu \cdot N$

where $\mu$ is the coefficient of static friction and N is Normal reaction

$N=mg$

$f_s=\mu mg$

$\mu mg=80$

$\mu =\frac{80}{27\times 9.8}$

$\mu =0.302$

7 0

4 years ago

Suppose the sun were to suddenly disappear. what would happen to the orbital path of earth? it would stay the same, but the eart

Vilka [71]

C: It would follow a path perpendicular to the radius of its current orbit

When there is nothing to keep it going in circles, it will stop moving in circles around the sun and continue in a straight path. Think of it as a catapult. If the stick stops, the rock keeps flying straight at the speed and direction it was flung.

7 0

3 years ago

Read 2 more answers

How would the earth move if the sun suddenly disappeared

Lerok [7]

Just a guess without asking Google, that without the sun's gravity holding us in orbit, we would end up drifting whatever direction we were headed as it disappeared?

4 0

3 years ago

An object is moving with a constant velocity of 278 m/s. How long will it take it to travel 7500 m, using the formula Delta X=Vt

rusak2 [61]

If the velocity is constant then the acceleration of the object is zero.
$a=0 (m/s^2)$
Thus when we apply the equation
$\Delta X=vt+(at^2/2)$
It remains
$\Delta X =vt$
or equivalent
$t=(\Delta X/v) =7500/278 =26.98 (seconds)$

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4 years ago

If you make multiple measurements of your height, you are likely to find that the results vary by nearly half an inch in either

Lisa [10]

Answer:

Height h= 1.7 m

Explanation:

Supposing we have to find height in meter.

1 feet = 0.3048 m

1 inch = 0.0254 m

Given that:

5 feet

= 5×0.3048

= 1.524 m

and 7 inch = 7×0.0254= 0.1778 m

Therefore total height of a man in meter

5 feet 7 inch = 1.5424+0.1778 =1.7 m

Height h= 1.7 m

8 0

3 years ago