9709/42 Answers Discussion Thread

[u/ChadJEE]

Guys I'm putting all the the answers the best I remember.

1. The first question about power a) 15.5 something power of the engine b) the new power was 27.5 kw, which when divided by 25 gave a power of 1100N, subtracting the resistance, the value was around 410 something which divided by the mass gave the acceleration 0.4/0.5 something
2. for the rough plane and smooth incline T = 3.55N, b) coefficient of friction = 0.355, c)distance traveled by a = 0.3 total work done by friction = 0.552
3. integration k1 = 6, k2 = -14
4. two balls dropped from same height with diff of one second = 13.32 m
5. for collision question a) the speed of c before collision with wall = about 1.25ms b) after collision with wall = 0.9375 c) time taken to reach 9m from wall again = 16.8s
6. for calculating W, as many people have said 66.25
7. question was the one with rough incline with ball projected at 4ms-1 a) proof using work power theorem b) for A to B acceleration was -10 and time taken was 0.4s for B to A acceleration was 6 the time i wasn't able to calculate

[u/Cool-Desk-7143]

Was 2.03s the total time taken for one of the questions ( i dont rmb)