1. Drag

2. Learning Objectives
(a) explain that an object travelling in a fluid experiences a resistive or a frictional force known as drag;
(b) state the factors that affect the magnitude of the drag force;
(c) determine the acceleration of an object in the presence of drag;

3. Drag Drag is a resistive force It depends on: velocity
cross-sectional area
Shape
Roughness of surface
It also is affected by the density of a gas or viscosity of a liquid

4. To calculate Drag F = 1/2 ρCdAv2 Where F = drag force ρ = density
Cd = coefficient of drag
V = velocity

5. We will take ρ as = 1.29kgm-3
For a rough sphere Cd = 0.48
For a flat plate = 1.28