January 2006
6678 Mechanics M2 Mark Scheme
Question Number 1.
Scheme
Marks
Kinetic Energy = 12 3 82 96, J
(a)
B1 B1 (2)
F 3g
(b)
B1
3gx12 = 96 0.27 or 0.272
Work-Energy
M1 A1ft A1 (4)
Alternative for (b)
a N2L
8 0 8 2 12 3 3g 3g 3 x 2
2
B1 8 3
M1 A1 A1
0.27 or 0.272
2.
r (2t 4)i (3 3t 2 ) j r3 10i 24 j
(a)
(4) 6 M1 A1 substituting t =3 M1
r3 102 242 26 ms1
(b)
(5)
0.4 v 10i 24 j 8i 12 j v 30i 54 j
3.
M1 A1
ms
12000 800 15 800 R 1000 0.2 R 600
1
ft their r3 M1 A1ft A1 (3) 8
Tr
(a) N2L
M1 ft their 800 M1 A1ft cso A1 (4)
(b)
1000 g
1 Tr R 40 7000 Tr U U 20
1
M1 A1 M1 accept 19.7
M1 A1 (5) 9