QUESTION ONE 1
An aeroplane of mass 2.5 - 10 kg lands with a speed of 62 m/s, on a horizontal runway at time
10. The aeroplane decelerates uniformly as it travels along the runway in a straight line until it
reaches a speed of 6.0 m/s at t = 355,
(a) Calculate:
(1) the deceleration of the aeroplane in the 35 s after it lands

The deceleration of the aeroplane is 1.6 m/s²

Explanation:

The speed of the aero plane after landing = 62 m/s

The time of deceleration of the aero plane = 35 seconds

The speed of the aero plane after deceleration for 35 s = 6.0 m/s

Therefore, we have the kinematic equation of motion of the aero plane, v = u - a·t

Where;

v = The final velocity = 6 m/s

a = The deceleration of the aero plane

t = The time of deceleration = 35 s

u = The initial velocity = 62 m/s

Substituting the values gives;

6 = 62 - a × 35

35·a = 62 - 6 = 56

a = 56/35 = 1.6

The deceleration of the aero plane = a = 1.6 m/s²

conservation of mass

mass before something happens = mass afterwards