hello, i re-wrought a sci question today...and so i am putting it on hear...i'll put the answer on to. (this is grade 10 sci...)
first one...
You are having fun on a water slide. You start from the top of the water slide, which is 2.7 m above the surface of the water. If you enter the water with the speed of 4.8 m/s, how efficient is the water slide in converting your gravitational potential energy into kinetic energy? Assume your mass is 58 kg.
re-wrought Question
Yuu kanda is dragged to the water park. Allen walker make's him go on a water slide, the water side is 2.7 m above the water surface. If he enters the water with the speed of 4.8 m/s,how efficient is the water slide in converting his gravitational potential energy into kinetic energy? assuming that Yuu's mass is 58 kg.
Answer
you need to find the Ek- Eg and the Eff-
Eff= (output/input) x 100
Ek is the output
Ek= MV^2 x 0.5
Ek= 58kg x 4.8^2 x 0.5
Ek= 668.16 J
that's the Ek, Now we need to find the Eg. :)
Eg= input
Eg= mgH
m= 58 kg H= 2.7 m we where not given g but g is earth's gravitational force it never changes, g= 9.81
Eg= 58 kg x 9.81 x 2.7
Eg= 1536.24
now we have both the Ek and the Eg. we can now find the Eff (efficient)
Eff= (output/input) x 100
Eff= (668.16/ 1536.24) x 100
Eff = ~43% (~ means about)
that's it that's all. a nice little sci. lesson