# Help with an air resistance problem.

• john12933
In summary, a raindrop with a mass of 1.06 × 10−5 kg falls in air and reaches a terminal speed of 4 m/s. The acceleration of gravity is 9.8 m/s2. To determine the resistive force F = k v, we need to find the value of the constant k. The answer should be in units of kg/s. To find the constant k, we can use the formula F = k v and plug in the values for the mass, terminal speed, and acceleration of gravity. This will give us an expression for the resultant force acting on the raindrop.
john12933
Part A)
A raindrop of mass 1.06 × 10−5 kg falls in air
and reaches a terminal speed of 4 m/s.
The acceleration of gravity is 9.8 m/s2 .
What is the value of the constant k that
determines the resistive force F = k v ?

Part B)
If there were no air resistance, how long would
it take the raindrop to reach the same speed?

I'm sorry there's no work, but I just have no idea where to start. We haven't even learned about air resistance in my class yet, and I was assigned this for homework.

john12933 said:
Part A)
A raindrop of mass 1.06 × 10−5 kg falls in air
and reaches a terminal speed of 4 m/s.
The acceleration of gravity is 9.8 m/s2 .
What is the value of the constant k that
determines the resistive force F = k v ?

Start by drawing a free-body diagram, what are the forces acting?

If the resultant force is downward, using the forces you listed, form an expression for the resultant force.

## 1. How does air resistance affect the motion of an object?

Air resistance is a force that acts against the motion of an object through air. It increases as the object's speed increases, and can cause the object to slow down or change direction.

## 2. How can air resistance be calculated?

The formula for calculating air resistance is F = 0.5 * p * v^2 * Cd * A, where F is the force of air resistance, p is the density of air, v is the velocity of the object, Cd is the drag coefficient, and A is the cross-sectional area of the object.

## 3. How can air resistance be reduced?

Air resistance can be reduced by making the object more streamlined, reducing its surface area, or increasing its velocity. Additionally, using materials with a lower drag coefficient can also help to reduce air resistance.

## 4. How does air resistance affect the trajectory of a projectile?

Air resistance can cause a projectile to deviate from its intended trajectory, as it acts in the opposite direction of the object's motion. This can result in a shorter distance traveled and a lower maximum height reached.

## 5. How does air resistance differ in different environments?

Air resistance can vary depending on factors such as altitude, temperature, and humidity. Thinner air at higher altitudes will result in less air resistance, while denser air at lower altitudes will result in more air resistance. Temperature and humidity can also affect air density, and therefore air resistance.

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