Physics

Problem

Three energy readings are noted in an experiment:

2.5\,\text{kJ}

3.60\times10^{5}\,\text{J}

, and

4.20\times10^{2}\,\text{J}

. Calculate the total energy and express your answer in scientific notation, giving the appropriate number of significant figures.

Intuitive explanation

The key here is unit conversion and significant figures in addition. First, convert all energies to the same unit (joules works best), then add them carefully—your final answer can only be as precise as your least precise measurement. When adding in scientific notation, line up the decimal places, not the exponents, to see which value dominates and where to round.

Intuitive explanation

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