Physics Quesition need help please

[aiyla]

A cricketer hits a ball straight up in the air, it leaves the bat at 16.8 ms-1 and has a mass of 160g .

i did part a) and b)  they asked for kinetic energy & height

now part c i don't know , the question says

c) if in reality, flying up in the air and back down again is process with an efficiency 88%, the how fast will the ball be traveling when it returns to the start point ?

please could some one explain the process and how exactlly should we solve this ?

[MaNi_DaDuDe]

I need to see the question and your answers to give you an answer..

I generally know that efficiency = work out/work in x 100% = (force * d)/(force * d) x 100%
In other words, ---> Actual/Ideal x100%

Don't really know how to help you, without seeing the real question.

FYI:


  I'm confused myself. lol.

[astarmathsandphysics]

Give me 5 mins to get to a pc

[astarmathsandphysics]

A cricketer hits a ball straight up in the air, it leaves the bat at 16.8 ms-1 and has a mass of 160g .

i did part a) and b)  they asked for kinetic energy & height

now part c i don't know , the question says

c) if in reality, flying up in the air and back down again is process with an efficiency 88%, the how fast will the ball be traveling when it returns to the start point ?

please could some one explain the process and how exactlly should we solve this ?
KE=1/2mv^2=0.08*16.8^2=22.5792
Final KE=0.88*22.5792=19.69J
1/2mv^2=19.69 so v=sqrt(19.69/(1/2*0.16))=15.76m/s

[aiyla]

the book Questions have no answers at the back, thats why its difficult to know if the answers are right or wrong .

[aiyla]

thanks alot mr.smith =D
i really appreciate it <3