1. **State the problem:** Calculate the electric force on a charge of $-2.91\,\mu C$ placed at $y=0.474\,m$ on the y-axis. 2. **Formula used:** The electric force between two point charges is given by Coulomb's law: $$F = k \frac{|q_1 q_2|}{r^2}$$ where $k = 8.99 \times 10^9\,N\cdot m^2/C^2$ is Coulomb's constant, $q_1$ and $q_2$ are the charges, and $r$ is the distance between them. 3. **Important rules:** - The force is attractive if charges have opposite signs and repulsive if they have the same sign. - The direction of the force is along the line joining the charges. 4. **Intermediate work:** - Convert $-2.91\,\mu C$ to Coulombs: $-2.91 \times 10^{-6}\,C$ - Identify the other charge and its position (not given in the problem, so assuming a known charge $q_1$ at origin or another point; since not specified, we cannot calculate numeric force without $q_1$). Since the problem only states the charge and position but does not provide the other charge or electric field, we cannot compute the force numerically. **If the problem assumes the charge is in an electric field $E$, then:** $$F = qE$$ where $E$ is the electric field at $y=0.474\,m$. Without additional information, the force cannot be calculated numerically. **Final answer:** More information is needed to calculate the electric force, such as the other charge or the electric field at the point.