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).
The thin layer of water that covers most earths surface is called the hydrosphere.
When multiple forces are at work on an object, the net force is called a <em>resultant</em>, because it's a sum of vectors, and a sum of vectors is called their resultant.
Answer:
The correct degree of precision is 272.94 g.
Explanation:
Precision : It is defined as the closeness of two or more measurements to each other.
For Example: If you weigh a given substance five times and you get 2.7 kg each time. Then the measurement is said to be precise.
Level of precision is determined by the maximum number of decimal places.
In the given figure, the value of mass of object is 280 g. From the given options we conclude that the 272.94 g is more close to 280 g and has maximum number of decimal places. So, 272.94 g measurement is said to be precise.
Therefore, the correct degree of precision is 272.94 g.
