Question

a stone is thrown vertically upwards with an initial velocity of 20 metre per second find the maximum height it reaches and the time taken by to reach the height( g =10m/s)​

Answer 1

Answer:

y = 20 [m]

Explanation:

To solve this type of problem we must use the following equation of kinematics.

$v_{f}^{2} =v_{o}^{2}-2*g*y$

where:

Vf = final velocity = 0

Vo = initial velocity = 20 [m/s]

g = gravity acceleration = 10 [m/s²]

y = elevation [m]

Now the key to solving this problem is to know that when the stone reaches the maximum height its speed is zero. Therefore the final velocity term is zero.

$0 = (20)^{2}-2*10*y\\20*y=400\\y=20 [m]$

Another important fact is that the sign of gravitational acceleration was taken as negative, since it acts in the opposite direction to the movement of the stone.