A its Stratosphere, Sorry I didn't see your answer, its bilogy I think not physics.. :)
Answer:
0.5sec
Explanation:
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Method one
Using the second law of motion
H=ut-1/2gt^2
20=5t-1/2×10×t^2
20=5t-5t^2
dh/dt = 5-10t
where any constant is zero therefore the 20 is zero
5-10t=0
Collect like terms
-10t= -5
t=1/2 = 0.5sec
2nd method
Parameters
Height(H) =20m
Initial velocity(u) = 5m/s
Acceleration due to gravity(g) =10m/s^2
Using the time taken formula
t=u/g
t=5/10
t=0.5sec
In order for two vectors to add to zero, they must have the same magnitude and point in opposite directions.
Two perpendicular vectors, by definition, make a right angle with each other whereas two vectors pointing in opposite directions form a straight line.
Because of this, two perpendicular vectors with nonzero magnitudes will never add to zero.
