Initial velocity

Question

A lorry travels 84m with a constant velocity on 2.0m/s²

^{to reach a velocity of 19m/s}

^{calculate the intial velocity}

Answer 1

I think the question must state the there is a constant ACCELERATION of 2 m/s²

^{If that is the case, then we use the equation of motion for final velocity (without time):}

v_f² = v_i² + 2aΔx where: "f" indicates final and "i" indicates initial; a is acceleration, and Δx is displacement

19² = v_i² + 2(2)84

361 = v_i² + 336

That yields:

v_i² 361 - 336 = 25

v_i = √25 = 5 m/s