By applying the second equation of motion, the speed at which he threw the second stone is equal to 12.10 m/s.
First of all, we would calculate the time taken by the first stone to reach a height of 49 meters by applying the second equation of motion as follows:
S = ut + ½gt²
49 = 0(t) + ½ × 9.8 × t²
49 = 4.9t²
t² = 49/4.9
t = √10
t = 3.16 seconds.
Now, we can determine the speed at which he threw the second stone:
Note: Time = 3.16 - 1 = 2.16 seconds.
S = ut + ½gt²
49 = u(2.16) + ½ × 9.8 × 2.16²
49 = 2.16u + 22.86
2.16u = 49 - 22.86
u = 26.14/2.16
u = 12.10 m/s.
Read more on initial speed here: https://brainly.com/question/19365526
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