Final answer:
The given calculation simplifies to 5.31 kg after converting units and rounding to the correct number of significant figures. Units are subject to multiplication and division just like numerical values in such calculations.
Step-by-step explanation:
The calculation in question is ((1.572 - 4.5x10-3) J/s) / (29.5 cm/s). First, we need to subtract the two values in the parentheses, which gives us 1.572 J/s - 0.0045 J/s = 1.5675 J/s. Then, we divide this result by the velocity, converting centimeters to meters by dividing by 100, which gives 29.5 cm/s = 0.295 m/s. So, the division is 1.5675 J/s / 0.295 m/s, which equals approximately 5.3144 kg, since 1 J/s divided by 1 m/s equals 1 kg. The answer should be rounded to three significant figures, because the least precise measurement (3.0 m/s) has two significant figures. So the final result is 5.31 kg.
When dealing with calculations that involve multiplication and division of different units, the units themselves are also subject to these operations. This means that units are either multiplied together or divided, depending on the operation applied to the corresponding numerical values. The result is an expression of the physical quantity in terms of the appropriate resulting unit.