1. The problem statement, all variables and given/known data An object undergoes acceleration 2.3i + 3.6j for 10s. At the end of this time, its velocity is 33i + 15j. a) What was its velocity at the beginning of the 10s interval? b) By how much did it's 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 time. why? 3. The attempt at a solution a) a→= Δv/Δt ∴ vi→ = (33i + 15j) - (23i + 36j) vi→ = (10i -21j) ms^-1 b) |vi→| = 23.26ms^-1 |vf→| = 36.25ms^-1 speed = |v| = (|vi→|) -|vf→| |v| = 13ms^-1 c)tanΘ = 15/33 Θ=24.45° d) |a→| = sqrt (2.3^2 + 3.6^2) = 4.272ms^-1 Δt = 10s |a→|.10s [itex]\neqΔv[/itex] ∴4.272ms^-1 . 10s [itex]\neq13ms^-1[/itex] what is the explanation?