Part (a). Performance was fair. Some of the respondent candidates failed to mention decrease in kinetic energy for the case of perfectly inelastic collision. Some candidates also failed to note that the question highlighted perfectly elastic collision and not ordinary elastic collision.
Part (b). Performance was high for (i), but low for (ii).
Part (c). This part was poorly tackled by candidates due to the use of wrong equations of motion and poor computational skills.
The expected answers are:
(a)Any 2 correct pairs

(c)(i) 1st stage of motion

x = ut + 1/2at²
120 = 0 x 12 + 1/2 X a x 12²
a= 5/3
V₁ = 5/3 x 12 = 20 ms^-1

2nd stage of motion
x = ut + 1/2at²
300 =, 20 x 12 + ½ x a x 12²
60 = 72a
a = 5/6

V = 5/6 x 12 = 10

V₂= 10 + 20
= 30ms·¹

3rd stage of motion

x = ut + 1/2at²
180 == 30 x 12 + ½ x a x 12²
180 = 72 a
a = - 5/2
V = -5/2 x 12= -30
V3 = 30 + -30
= 0 ms·¹

(ii)

Correct shape of each segment in relation to axes
Origin, (0.0) labeled
Only one axis labeled