Relative Motion in Physics: Velocity Calculation Example

Understanding Relative Motion:

Relative motion in physics refers to the observation of motion from a frame of reference that is in motion itself. When dealing with relative motion, it is essential to consider the velocity of different objects relative to each other, rather than absolute velocities.

Calculation Method:

When calculating the velocity of the cannonball for an observer on a stationary ship next to the moving battleship, we need to consider both the velocity of the cannonball relative to the battleship and the velocity of the battleship itself. By subtracting the velocity of the battleship from the relative velocity of the cannonball, we determine the velocity of the cannonball for the observer on the stationary ship.

Result Interpretation:

In this specific scenario, where the cannonball is fired backward at 100 m/s relative to the ship and the battleship is moving forward at 20 m/s, the velocity of the cannonball for the observer on the stationary ship is calculated to be -120 m/s. The negative sign indicates that the cannonball is moving in the backward direction relative to the stationary ship, despite being fired backward relative to the battleship.

Conclusion:

Understanding relative motion is crucial in physics to accurately analyze the movement of objects in different frames of reference. By applying the concept of relative velocity, we can calculate the motion of objects relative to one another and determine their observed velocities from different perspectives, such as in the example of the cannonball fired from a moving battleship. This calculation provides valuable insight into how objects interact and move relative to each other in complex motion scenarios.