An object undergoes acceleration 2.3i 3.6j m/s2 for 10 s. At the end of this time, its velocity is 33i 15j m/s. (a) What was its velocity at the beginning of the 10-s interval? (b) By how much did its speed change? (c) By how much did its direction change? (d) Show that the speed change is not given by the magnitude of the acceleration multiplied by the time. Why not?