Question

A metal ball of mass 5 kg falls from a height of 490 m .How much time will it take to reach the ground.(g=9.8m/s2).​

Answer 1

Answer:

Time required to reach the ground is 10 seconds

Explanation:

Given

Mass of metal ball = 5 kg

Initial height (hi) = 490 m

gravitational acceleration g = 9.8 m/ s²

Time to reach ground (t) = ??

Solution

By using equation of motion

h = Vi t + 1/2 at² .......................(i)

Final height (hf) = 0 m

Initial velocity (Vi) = 0 m/s

we can write equation i

hf - hi = Vi t + 1/2 at²

hf = hi + Vi t + 1/2 at²

by putting values

0 m = 490 m + (0) t - 9.8/2 t² (acceleration is in negative direction)

t² =  490/ 4.9

t = √100

t = 10 s