1. A train from rest, accelerates at 1.8m/s2 for 30s. the train driver then suddenly notice an obstacle ahead and brakes immediately at 5 m/s2 to stop after 15s of braking.

   a) Draw the velocity vs time graph of the motion; 

   b) Find the total distance travelled. [5]
2. A particle undergoes a uniformly accelerated motion on which flashes a strobe every 0.5 seconds. It took 30 seconds to cover the full observation, and the distances travelled during the first 0.5 s and the last 0.5 s of observation was 25 m and 84 m respectively. Determine:  

    a) the acceleration of the particle; 

    b) the total distance travelled during the full observation; 

    c) velocities of the particle at the beginning and at the end of observation respectively; the total distance the particle is expected to travel between the 5th and the 10th minutes. [10]
3.Two masses of 16 kg and 4 kg approach each other head-on with speeds of 3 m/s and 5 m/s respectively.  With what velocity does the combined wreckage move after the collision? [5]