posted by Norman on .
Stickman is driving a dragster. He does the quarter mile in 4 seconds and at the finish line is speed is 100m/s. He deploys his parachute after he crosses the finish line and wished to slow to a speed of 10m/s in 10s. What diameter parachute does he need if the drag force is equal to -Av^2 (A is the shoot area=pir^2 in m^2)
The resistive force acting on the dragster is f=-Av^2
you know the following
v= speed of the dragster at any time after stickman crosses the finish line
vi=100m/s=speed of the dragster as stickman crosses the finish line
g=acceleration due to gravity
1)write newton's second law equation for the dragster any time after stickman crosses the finish line.
2) solve newton's second law equation to determine an expression for the area of the parachute attacked to the dragster at any time after stickman crossest eh finish line.
3)determine the diameter of the parachute needed to slow the dragster down from 100m/s to 10m/s in 10s.
#2 just solve for a
#3 Plug in. A=9m^2 then plug into formula and solve for d