Answer:
Initial velocity of rock = 11.6 m/s
Explanation:
Given:
Final velocity of rock = 90 m/s
Time taken by rock = 8 seconds
Find:
Initial velocity of rock
Computation:
Using first equation of motion;
v = u + at
For rock
v = u + gt
Acceleration due to gravity = 9.8 m/s²
90 = u + (9.8)(8)
90 = u + 78.4
u = 90 - 78.4
u = 11.6
Initial velocity of rock = 11.6 m/s
