The height of the ball above the ground is 38.45 m
First we will calculate the velocity of the ball when it touch the ground by using first equation of motion
v=u+gt
v=0+9.81×2.8
v=27.468 m/s
now the height of the ground can be calculated by the formula
v=√2gh
27.468=√2×9.81×h
h=38.45 m
Answer:

Explanation:
Two identical bodies are sliding toward each other on a frictionless surface.
Initial speed of body 1, m₁ = 1 m/s
Initial speed of body 2, m₂ = 2 m/s
They collide and stick.
We need to find the speed of the combined mass. Let V is the speed of the combined mass.
Using the conservation of momentum.

We have, m₁ = m₂ = m

So, the speed of the combined mass is
.
Answer: C
Explanation:
Find the acceleration using this kinematic equation:

Now use this kinematic equation to find the displacement:

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