Try driving a T-top at 60 mph with the catches open ... you'll soon realise that increasing the speed of the air over the car causes lift
then,
to confirm the results of that test, try holding a spoon vertically under a running tap with the water flowing over the convex side of the spoon and note the force pulling the spoon into the flow of water
then,
when you've done all that, post your conclusions on here
but please please please,
check your spelling and grammar before you do