What would be the final velocity for an airplane that starts at the beginning of a 4km runway with an initial velocity of 60 km/h accelerating at 1.2×104 km/h^2 if the pilot uses the entire runway before liftoff? A. 22.5×10^5 B. 1.0×10^5 C. 3.16×10^2 D. 9.6×10^4 PLEASE HELP I KEEP GETTING THE WRONG ANSWER

2.12×10^-2hour

Explanation:

Acceleration is defined as the change in velocity of a body with respect to time.

Using one of the equations of motion:

S = ut + 1/2at²

Where S is the distance traveled by the airplane

u is the initial velocity

a is its acceleration

t is the time of travel

Given a = 1.2×104 km/h²

u = 60km/hr

t= ?

S = 4km

Substituting the values given into the formula to get 't'

4 = 60t+1/2(1.2×10⁴)t²

4 = 60t+0.6×10⁴t²

0.6×10⁴t²+60t-4= 0

Factorizing the quadratic equation

t = -b±√b²-4ac/2a

Where a= 6000 b = 60 c = -4

t = -60±√60²-4(6000)(-4)/2(6000)

t = -60±√3600+96000/12000

t = -60±√99600/12000

t = -60±315.6/12000

t = -60+315.6/12000

t= 255.6/12000

t = 0.0212hour

t = 2.12×10^-2hour

the correct answer is b

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