How long will it take an airplane at rest that accelerates uniformly at 2.5 m/s to reach a ground
velocity of 70 m/s that is required for takeoff

28 seconds.

Explanation:

Apply the first equation of motion as;

v=u +at where;

v= final velocity of the plane = 70m/s

u=initial velocity of the plane= 0m/s it was at rest

a= acceleration uniform =2.5 m/s²

t= time required for takeoff = ?

Substitute values in the equation as;

v= u + at

70 = 0 + 2.5*t

70 = 2.5t

70/2.5 = 2.5/2.5t

28 = t

Time required for takeoff is 28 seconds.

Explanation:

Use the one-dimensional equation

where v is the final velocity, v0 is the initial velocity, a is the acceleration, and t is the time it takes to reach that final velocity. We are solving for t. Filling in the other values:

0 = 28 + (-6.4)t and

-28 = -6.4t so

t = 4.4 seconds