Answer:
h = 9.57 seconds
Explanation:
It is given that,
Initial speed of Kalea, u = 13.7 m/s
At maximum height, v = 0
Let t is the time taken by the ball to reach its maximum point. It cane be calculated as :




t = 1.39 s
Let h is the height reached by the ball above its release point. It can be calculated using second equation of motion as :

Here, a = -g


h = 9.57 meters
So, the height attained by the ball above its release point is 9.57 meters. Hence, this is the required solution.

The net force acting on the block is ~


So, the Answer in the boxes will be ~

Answer:
Time use of cellphone times 3 hours before sleep.
Explanation:
It is scientifically proven that cell-phone use before bed can disturb your sleep. The blue light can cause your brain to release chemicals that associate with staying awake or even waking up. So measure the hours or minutes you use your phone 3 hours before you go to sleep.
Answer B is the correct answer
We know that kinetic energy
, where m is the mass of object and v is the velocity of object.
In this case only velocity is the variable, mass remains constant.
So point having higher velocity has higher kinetic energy.
When it leaves the racket, the ball will be having a certain height, but just before it reaches the ground it will not having any height. So maximum velocity of ball is at that time when it reaches just above the ground.
So option B is the correct answer.