Answer:
7.23 m/s
Step-by-step explanation:
From Newton's equation of motion,
v = u + at ...................... Equation 1.
Where v = final velocity, u = initial velocity, a = acceleration, t = time.
Also,
s = ut+ 1/2at²........................ Equation 2
Where s = distance.
Given: t = 8.8 s, s = 45.0 m.
Substitute into equation 2
Note: we find the value of a in terms of u
45 = u(8.8)+1/2a(8.8)²
45 = 8.8u+38.72a
38.72a = 45 -8.8u
38.72a = (45-8.8u)
a = (45-8.8u)/38.72
also, v = 3.00 m/s
Substituting into equation 1
3 = u + 8.8[(45-8.8u)/38.72)]
3 = u + (45-8.8u)/4.4
3×4.4 = 4.4u + 45 - 8.8u
13.2 - 45 = 4.4u - 8.8u
-31.8 = -4.4u
u = -31.8/-4.4
u = 7.23 m/s.
Hence the initial velocity = 7.23 m/s