6. Mechanical power (a) (i) = 2 (ii) = = 1.2 104 300 = 3.6 106 J; 1    W mgh (iii) work done against friction = 4.8 103 5.0 102;    work done = 2.4 106 + 3.6 106;   total work done = = 6.0 106; P  t  to give 4 (d) (i) sin = weight down the plane = sin = 1.2  104  0.047 = 5.6  102N; W net force on car = 5.6  102 5.0  102 = 60N; F 5 (ii) = 2as = 2 5.0 102 6.4 103;     v2 to give = 25ms1; 2 v (e) 5.6 102 N; 1 
6. Mechanical power (a) (i) = 2 (ii) W = mgh = 1.2  104  300 = 3.6  106 J; 1 (iii) work done against friction = 4.8  103  5.0  102; work done = 2.4  106 + 3.6  106; total work done = P  t = 6.0  106; to give 4 (d) (i) sin = weight down the plane = W sin = 1.2  104  0.047 = 5.6  102N; net force on car F = 5.6  102 5.0  102 = 60N; 5 (ii) v2 = 2as = 2  5.0  102  6.4  103; to give v = 25ms1; 2 (e) 5.6  102 N; 1
energy_questions_markscheme.docx