In the context of the graph of forces exerted by different motors versus their accelerations, we can use Newton's second law, which states that \( F = ma \), where \( F \) is the force, \( m \) is the mass, and \( a \) is the acceleration.
If we rearrange this equation to express force in terms of acceleration, we can write:
\[ F = m \cdot a \]
This implies that if we were to graph force (F) on the y-axis and acceleration (a) on the x-axis for a constant mass (m), the equation can be interpreted as:
\[ F = m \cdot a \Rightarrow F = m \cdot a + 0 \]
In this equation, the slope of the graph would be the mass (m), and the y-intercept would be zero because when acceleration \( a = 0 \), the force \( F \) is also \( 0 \).
Thus, the y-intercept of the graph is zero.