## A 60 Kilogram Skydiver Falling at a Constant Speed
When a skydiver jumps out of a plane, they experience a brief period of freefall before their parachute opens. During this time, the skydiver is accelerating downward due to the force of gravity. However, once their parachute opens, the force of drag acting on the skydiver becomes equal to the force of gravity, and they reach a constant velocity.
### Forces Acting on a Skydiver
The following forces are acting on a skydiver in freefall:
* **Gravity:** The force of gravity is pulling the skydiver down towards the Earth. This force is proportional to the mass of the skydiver.
* **Drag:** The force of drag is acting opposite to the direction of the skydiver’s motion. This force is proportional to the square of the skydiver’s velocity and the area of the skydiver’s body that is exposed to the air.
### Constant Velocity
When the force of gravity is equal to the force of drag, the skydiver reaches a constant velocity. This is known as the terminal velocity. The terminal velocity of a skydiver depends on their mass, body size, and the density of the air.
For a 60 kilogram skydiver, the terminal velocity is approximately 120 miles per hour. This means that the skydiver will continue to fall at a constant speed of 120 miles per hour until their parachute opens.
### Parachute Opening
When the skydiver pulls the cord to open their parachute, the surface area of their body that is exposed to the air increases dramatically. This causes the force of drag to increase, which slows the skydiver down.
The skydiver will continue to decelerate until they reach a new terminal velocity. The terminal velocity of a skydiver with an open parachute is much lower than the terminal velocity of a skydiver in freefall. This is because the increased drag force acting on the skydiver is greater than the force of gravity.
### Landing
The skydiver will continue to fall at a constant speed until they land on the ground. The impact of landing can be significant, so it is important for skydivers to land on their feet and roll to absorb the impact.
## Conclusion
A 60 kilogram skydiver falling at a constant speed is an example of Newton’s second law of motion. The force of gravity acting on the skydiver is equal to the force of drag acting on the skydiver, resulting in a constant velocity. When the skydiver opens their parachute, the force of drag increases, which slows the skydiver down and results in a new terminal velocity.
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