Question

1. Skydivers experience terminal speed.

(a) State what terminal speed is and how it occurs

(b) Explain the effect opening a parachute has on the skydiver's terminal speed

2. A car is driving at constant speed along a flat road.

(a) State the net force on the car.

(b) Draw a diagram of the car, and four forces (including vertical forces) acting on the car. Make sure vectors (arrows) that should be the same length, are the same length.

3. Two students are sitting in small boats and pulling on a rope:

(a) The student on the left is pulling with 432 N. State how much force the student on the right is pulling with.

(b) The student on the left and his boat have a total mass of 103 kg, and the friction of the water is 98.1 N. Calculate the acceleration of the student on the left.

I want it clear. please  

Answer 1

1 a) Terminal speed:-Terminal speed is the velocity at which a falling object (falling due to gravitational force) ceases to accelerate downward. A falling object begins at zero velocity and accelerates down, picking up speed until drag, or resistance, causes the object to cease accelerating and continue down at a constant velocity.

It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object. Since the net force on the object is zero, the object has zero acceleration.

b) An open parachute increases the cross-sectional area of the falling skydiver and thus increases the amount of air resistance which he encounters . Once the parachute is opened, the air resistance overwhelms the downward force of gravity. The net force and the acceleration on the falling skydiver is upward. An upward net force on a downward falling object would cause that object to slow down. The skydiver thus slows down. As the speed decreases, the amount of air resistance also decreases until once more the skydiver reaches a terminal velocity.