Where appropriate, show your methods clearly (and fully) in questions 3 and 4. 3. There are four force vectors acting within the internal combustion chamber of a car engine. Positions of three of the vectors from a fixed point of origin are: a = (1,1,2), b = (-1,2,2) and C = (0, 3,4). (a) Write the three positional vectors in terms of i, j and k components. The answers are started for you below: a = (1,1,2) = ?i, ?j, ?k = b = (-1,2, 2) = C = (0, 3,4) = (b) Find the fourth force vector d in terms of i, j and k, given that if d = a + 2b - 3 (c) Find the magnitude of d and write down the unit vector d in the direction of d. (d) What are the direction cosines of d