Aphysics student stands on a cliff overlooking a lake and decides to throw a tennis ball to her friends in the water below. she throws the tennis ball with a velocity of 25.5 m/s at an angle of 33.5∘ above the horizontal. when the tennis ball leaves her hand, it is 18.5 m above the water. how far does the tennis ball travel horizontally before it hits the water? neglect any effects of air resistance when calculating the answer.

Explanation:

Given

Initial velocity(u)=25.5 m/s

Projection angle

ball is 18.5 m above the ground

Time of flight for zero vertical displacement is

its vertical velocity will be equal to initial vertical velocity but it will be downward direction at the completion of zero vertical displacement

Now time taken to cover 18.5 m vertical displacement

t=0.979 s

Thus

Total time to reach ground

Horizontal Distance traveled in 3.85 s

this allows people to make the best decision or pursue the best option. when alternatives are weighed using their advantages and disadvantages, the option whose disadvantages outweigh the advantages (based on a qualitative or quantitative analysis) are shunned while those whose advantages outweigh their disadvantages are pursued.  

it is called kinetic energy