# Forces: Terminal Velocity

## Forces: Terminal Velocity

### Terminal Velocity:

• Terminal velocity is the highest speed an object will reach when falling through a fluid, like air or water.
• It occurs when the drag force (force opposing the motion) equals the gravitational force pulling the object downwards.
• At this point, there is no acceleration, as the forces are balanced, meaning the velocity of the object becomes constant.
• The value of terminal velocity depends on the shape, size, and mass of the object, as well as the density of the fluid it is falling through.

### Drag Force:

• Drag force, also known as air resistance, opposes the motion of an object.
• The amount of drag force depends on the speed of the object. The faster an object moves, the greater the drag force.
• The object’s surface area also directly impacts the drag. Larger surface areas experience more drag force.

### Free Fall and Terminal Velocity:

• Initially, when an object first falls, it accelerates due to gravity, and there is little air resistance.
• As speed increases, the air resistance increases until it is equal to the weight of the object.
• At this point, terminal velocity is reached, and the object falls at a steady speed.

### Factors affecting Terminal Velocity:

• Mass: Heavier objects have a greater terminal velocity.
• Shape and Size: Streamlined objects face less air resistance, resulting in a higher terminal velocity than less aerodynamic objects. Similarly, smaller objects experience lesser drag.
• Density of the Fluid: The denser the fluid, the greater the drag force, reducing terminal velocity.

### Graphical representation:

• On a velocity-time graph for an object falling at terminal velocity, the flat, horizontal line represents terminal velocity.
• The steep part at the start of the graph represents the acceleration phase where the object is gaining speed.
• The point where the graph starts to level off, indicating the object’s speed is no longer increasing, is when terminal velocity is reached.