Sasha needs to calculate when an object will hit the ground if it is launched with an initial velocity of 15 meters per second and at an initial height of 40 meters. Her work is shown below. First, I’ll write a quadratic function using the model h(t) = 1 2 gt2 v0t h0, where the values to substitute in are g = –9.8, v0 = 15, and h0 = 40. h(t) = 1 2 (–9.8)t2 15t 40 Next, I’ll simplify the first term. h(t) = –4.9t2 15t 40 Then, I’ll solve the quadratic function using the quadratic formula, using a = –4.9, b = 15, and c = 40. t = –15 ± �(15)2– 4(−4.9)(40) 2(-4.9) I can simplify, following the order of operations. t = –15 ± √1009 -9.8 I’ll use a calculator and approximate the solutions. t ≈ –1.71 or 4.77 The object hit the ground at about –1.71 seconds and 4.77 seconds Critique Sasha’s work by explaining any errors she made, and justifying correct solutions.