An object has a kinetic energy of 810 J after falling a certain distance. If the mass of the object is 20 kg,?

1 ⤊

....what is the speed of the object at this time??

2007-03-12 06:39:07 · 3 answers · asked by Baby Gurl 1 in Science & Mathematics ➔ Chemistry

Fundamental equation:

E = 1/2 m v^2

Since E = 810 J, and m = 20 kg, solve for v:

810 = 1/2 * 20 * v^2
v^2 = 81
v = 9 meters per second

2007-03-12 06:43:41 · answer #1 · answered by Keith P 7 · 1⤊ 0⤋

K.E=1/2mvv (v square)
810=1/2*20*vv
vv=810/10
vv=81
v=9

2007-03-12 06:45:44 · answer #2 · answered by Anonymous · 0⤊ 0⤋

Ek = mv²/2 so
810 = 20v²/2 and with a bit of algebra
v = √(2*810/20) = √(1620/20) = √81 = 9 m/s

HTH ☺

Doug

2007-03-12 06:47:05 · answer #3 · answered by doug_donaghue 7 · 0⤊ 0⤋