1. The problem is to find the force $F$ which is given as 378 N. 2. The formula for force in Newtonian mechanics is $F = ma$, where $m$ is mass and $a$ is acceleration. 3. Since the answer is already given as $F = 378$ N, we assume the calculation or measurement is complete. 4. Therefore, the force acting is $\boxed{378}$ N.