Question

A plane with an unknown mass sits at rest. The pilot turns the pair of jet engines to full throttle , and the thrust accelerates the plane down the runway. after traveling 800 m the plane reaches its takeoff speed of 70 m/s and leaves the ground. What is the mass of the plane ? Round answer to nearest whole N

Answer 1

let m is the mass of the plane.

initial velocity, vi = 0
distance travelled before take off, d = 800 m
final velocity, vf = 70 m/a

acceleration of the plane, a = (vf^2 - vi^2)/(2*d)

= (70^2 - 0^2)/(2*800)

= 3.0625 m/s^2

from the given data, we can not find mass.
we can only find acceleration.

and units of mass is kg,but not N.

If thrust on the plane is give, we can find mass of the plane.

m = F_thrust/a

if mass of the plane is given we can find thrust.
using, F_thrust = m*a

Note: please comment foe any further help.