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2 years ago

3.

Physics

1 answer:

ratelena [41]2 years ago

8 0

Answer:

1.84 kJ (kilojoules)

Explanation:

A specific heat of 0.46 J/g Cº means that it takes 0.46 Joules of energy to raise the temperature of 1 gram of iron by 1 Cº.

If we want to heat 50 g of iron from 20° C to 100° C, we can make the following calculation:

Heat = (specific heat)*(mass)*(temp change)

Heat = (0.46 J/g Cº)*(50g)*(100° C - 20° C)

[Note how the units cancel to yield just Joules]

Heat = 1840 Joules, or 1.84 kJ

[Note that the number is positive: Energy is added to the system. If we used cold iron to cool 50g of 100° C water, the temperature change would be (Final - Initial) or (20° C - 100° C). The number is -1.84 kJ: the negative means heat was removed from the system (the iron).

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andrew11 [14]

Answer:

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Explanation:

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pashok25 [27]

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Initial velocity,u = -2 m/s

Final velocity,v = -10 m/s

Time taken, t = 4 seconds

$\bf \underline{To \: find \: out : }$

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