Question

Qual a energia cinética de um a partícula de massa 5000g, cuja a velocidadd vale 72km/h?

Answer 1

Colocando no SI

5000g = 5 Kg
72 km/h = 20 m/s


Calculamos


EC = mV²/2
EC = 2,5*20²
EC = 2,5*400
EC = 1000 J

Answer 2

$\sf m=5000\,g$

$\sf m=5\,kg$

$\sf v=72\,km/h$

$\sf v=20\,m/s$

$\sf E_c=\dfrac{1}{2}\cdot m\cdot v^2$

$\sf E_c=\dfrac{1}{2}\cdot5\cdot20^2$

$\sf E_c=2{,}5\cdot400$

$\boxed{\boxed{\sf E_c=1000\,J}}$