- #1
Kajan thana
- 151
- 18
Homework Statement
A ball is thrown horizontally wit speed 20m/s, from the top of the building which is 30m high.
Find the time the ball takes to reach the ground?
Homework Equations
S= ut+0.5at^2
The Attempt at a Solution
S=-30
u=0
A=9.8
T=?
When I pluck the values I will get t^s=-30/4.9 but when we square root we will get complex number, but if I take the displacement as +30 then it will give me a positive value, so I am confused on why the s is not negative.
If I say the displacement where the ball is on top of the building, then the displacement is 0 but if it goes down then it should be negative value.