Will the mass of the object ( as in a car ) affect the drag or lift force. WIll the car have the same drag/lift forces when the shape or size of the car is kept constant and the mass alone is varied. Explain if the drag/lift forces will not change !
It will not change. It will depend only on the shape / size of the car and the speed.
The mass wont affect the air drag if the shape remains the same. At standstill, the only force (Newtons) is the mass of the car acting down under gravity ( m * g ) Assuming moving air creates the lift, once you are moving there is a lift force and the faster you go the more the lift force is, so the net vertical force downwards diminishes with speed. Summary: Horizontally, no changes with mass. Vertically , net downward force diminishes with speed.
Drag D 1/2 rho Cd Ax V^2 Lift L 1/2 rho Cl Al V^2 rho is air density in kg/m^3, Cd is drag coefficient a measure of streamlineness, V is relative speed of the windstream, Ax is cross sectinal area, Cl is lift coefficient, and Al is the lift area (typically the wing and tail upper areas). As you can see, the mass of the body, m, does not enter into drag or lift. But the shape of the body does in the two coefficients and the two areas. It should not be a surprise that the two relationships are similar. They are both derived from the laws of fluid dynamics. [See source.] Just thought of something, perhaps you should know that net lift l L - W L - mg does depend in part on the mass of the object. That results because the net lift is the lift minus the weight of the object. And weight W mg depends on the mass, m. As you can see, when l 0 L - mg so the object is flying level the left must be L W equal to the weight of the object. And logically, when L mg the object rises and when L mg, the object descends.
