Question

A 3.00 kg toy falls from a height of 1.00 m. What will the kinetic energy of the toy be just before the toy hits the ground? (Assume no air resistance and that g = 9.81 m/s656-06-03-00-00_files/i0090000.jpg.)

Answer 1

Kinetic energy formula: Ek = m · v² / 2
We have: m= 3 kg, v= ?
h= g·t²/2 , t²= 2h/g = 2 m / 9.81 m/s² = 0.2 s² , t=√0.2(sqrt)= 0.45 s
v= g· t = 9.81 m/s² · 0.45 s = 4.43 m/s
Finally: Ek=
`(m v^(2) )/(2) = (3 kg * (4.43 m/s)^(2) )/(2) = (58.87 J)/(2)`= 29.43 J