**Final Answer:**
If you are driving a tanker that is 3/4 full and you are forced to brake hard, you can expect the liquid inside the tanker to surge forward due to inertia, creating a risk of the tanker overturning or losing control.
**Explanation:**
When a vehicle brakes suddenly, the liquid inside a partially filled tanker continues to move forward due to inertia while the tanker slows down. This phenomenon is governed by Newton's First Law of Motion, which states that an object in motion tends to stay in motion unless acted upon by an external force. In this case, the sudden braking applies a force on the tanker, but the liquid inside tends to resist changes in its motion.
The force that causes this surge is calculated using the equation F = ma, where F is the force, m is the mass, and a is the acceleration. When braking, the vehicle decelerates (negative acceleration), causing a force against the liquid. The force exerted on the liquid depends on the mass of the liquid and the rate of deceleration.
The specific gravity of the liquid also plays a crucial role. For instance, if the tanker is carrying a liquid with a higher specific gravity, it will exert more force due to its greater mass. Furthermore, the design and shape of the tanker affect its stability during sudden braking, as a higher center of gravity or improper weight distribution can increase the risk of overturning or loss of control.
Therefore, when driving a tanker that is 3/4 full and forced to brake hard, the surge of liquid due to inertia can lead to potentially dangerous situations, making it crucial to exercise caution and follow safety protocols to prevent accidents or spills.