Well, the 20 seconds gives us enough information to actually calculate the power she has on her feet :)
Well, the work is 500*15=7500J, that is 7.5 kJ or about 18 calories (1 cal is 418J?) The power is that 7.5 kJ divided by 20 seconds: 375W. That's... OK, I suppose...
Considering the equivalence between mass and energy given by the expression of Einstein's theory of relativity, the correct answer is the last option: the energy equivalent of an object with a mass of 1.05 kg is 9.45×10¹⁶ J.
The equivalence between mass and energy is given by the expression of Einstein's theory of relativity, where the energy of a body at rest (E) is equal to its mass (m) multiplied by the speed of light (c) squared:
E=m×c²
This indicates that an increase or decrease in energy in a system correspondingly increases or decreases its mass, and an increase or decrease in mass corresponds to an increase or decrease in energy.
In other words, a change in the amount of energy E, of an object is directly proportional to a change in its mass m.
In this case, you know:
Replacing:
E= 1.05 kg× (3×10⁸ m/s)²
Solving:
<u><em>E= 9.45×10¹⁶ J</em></u>
Finally, the correct answer is the last option: the energy equivalent of an object with a mass of 1.05 kg is 9.45×10¹⁶ J.
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Answer: Mathematical Model
Explanation:
Took the test
Answer:
Explanation:
<u>Average Speed
</u>
If an object travels a distance d in a time t regardless of the direction, the average speed is the quotient of the distance over the time:
It's known a person runs d=15 kilometers in t=2 hours, thus his/her average speed is:
Calculating:
