Exercise 6.10
The acceleration-mass graph for the acceleration produced by a force on objects of different masses is plotted in Fig. 6.40. Plot the force-mass graph for this case. Acceleration (m ) 
Not cross-checked
NCERT prints no numerical answer for this exercise, so this working has not been cross-checked against the book.
The force-mass graph is a straight line parallel to the mass axis at the constant value \(\displaystyle F = 10\ \text{N} \).
The same force acts on every object, so from Newton's second law \(\displaystyle F = ma \) the product of mass and acceleration is the same for all the points on Fig. 6.40.
Reading the graph: at \(\displaystyle m = 1\ \text{kg} \), \(\displaystyle a = 10\ \text{m s}^{-2} \), so \(\displaystyle F = 1\ \text{kg} \times 10\ \text{m s}^{-2} = 10\ \text{N} \).
Check another point: at \(\displaystyle m = 2\ \text{kg} \), \(\displaystyle a = 5\ \text{m s}^{-2} \), giving \(\displaystyle F = 2 \times 5 = 10\ \text{N} \); and at \(\displaystyle m = 4\ \text{kg} \), \(\displaystyle a = 2.5\ \text{m s}^{-2} \), giving \(\displaystyle F = 4 \times 2.5 = 10\ \text{N} \).
What to draw: mark Mass (kg) on the horizontal axis from $\displaystyle 0$ to $\displaystyle 5$ and Force (N) on the vertical axis from $\displaystyle 0$ to about 15. Plot the points $\displaystyle (1, 10)$, $\displaystyle (2, 10)$, $\displaystyle (3, 10)$, $\displaystyle (4, 10)$ and $\displaystyle (5, 10)$ and join them with a straight horizontal line. Label the line \(\displaystyle F = 10\ \text{N} \).
The graph is horizontal because the force is the same whatever the mass — the acceleration-mass curve falls as \(\displaystyle a = \dfrac{10}{m} \) precisely so that \(\displaystyle ma \) stays fixed.