Answer:
(C) speed = 40 m/s, distance = 80 m
Explanation:
According to Newton law of motion for a falling body:
v = u + gt
Where v is the final velocity, u is the initial velocity, t is the time taken to fall and g is the acceleration due to gravity.
Given that: t = 4 s, g = 10 m/s², u = 0 m/s(at top of building). Therefore substituting values:
v = 0 + 10(4)
v = 40 m/s
To find the distance h, we use the formula:
v² = u² + 2gh
Substituting values:
40² = 0² + 2(10)h
20h = 40² - 0²
20h = 1600
h = 1600 / 20
h = 80 m
The speed = 40 m/s, distance = 80 m