Chapter 3, Problem 26A

An apple weighs about 1 N. What is its mass in kilograms? What is its weight in pounds?

To determine

The mass of an apple in kilograms for a given weight. Also, the weight in pounds.

Answer to Problem 26A

The mass of the apple in kilograms is $0.102\text{}\text{kg}$.

The weight of the apple in pounds is $0.046\text{lbs}$.

Explanation of Solution

Given:

An apple weighs about 1 N.

Formula used:

The weight of an object is the force it experiences due to the force of gravity exerted by earth on it. It can be expressed as,

  $W=mg$

Here, mass is expressed in kilograms and the acceleration due to gravity on earth is considered which is $g=9.8{\text{ m/s}}^2$ .

Now, pounds are a measure of the quantity of matter on the surface of earth. It is related to kilogram as,

  $1\text{kg}=2.2\text{ lbs}$

Calculation The weight of the apple is given as 1 N. From this, the mass in kilogram can be obtained as,

  $\begin{array}{c}m=\frac{W}{g}\\ =\frac{1}{9.8}\\ =0.102\text{ kg}\end{array}$

Now, the weight of the apple in pounds is given by,

  $\begin{array}{c}{W}_p=\frac{0.102}{2.2}\\ =0.046\text{ lbs}\end{array}$

Conclusion:

The mass of the apple in kilograms is $0.102\text{}\text{kg}$ and the weight of the apple in pounds is $0.046\text{lbs}$