Question

Two 3.7 kg physical science textbooks on a bookshelf are 0.33 m apart. What is the magnitude of the gravitational attraction between the books?

Answer 1

Universal gravitational constant \(G=6.67 \times 10^{-11} \frac{\mathrm{N} \cdot \mathrm{m}^{2}}{\mathrm{~kg}^{2}}\)

Mass of two text books \(m_{1}=m_{2}=3.7 \mathrm{~kg}\) The books are separated by a distance \(r=0.33 \mathrm{~m}\)

The magnitude of gravitational attraction between the books is

$$ \begin{aligned} F &=\frac{G m_{1} m_{2}}{r^{2}} \\ &=\frac{\left(6.67 \times 10^{-11} \frac{\mathrm{N} \cdot \mathrm{m}^{2}}{\mathrm{~kg}^{2}}\right)(3.7 \mathrm{~kg})(3.7 \mathrm{~kg})}{(0.33 \mathrm{~m})^{2}} \\ =& 8.38 \times 10^{-9} \mathrm{~N} \end{aligned} $$