Question

qual a energia cinética de uma particula de massa 5000g cuja a velocidade vale72km/h?

Answer 1

Dados:

m = 5 000 g ÷ 1 000 ⇒ 5 kg

v = 72 km/h ÷ 3,6 ⇒ 20 m/s

Ec = ?

_

$Ec \ = \ \frac{m \ * \ v^{2 }} {2}$


$Ec \ = \ \frac{5 \ * \ (20 )^{2} }{2}$

$Ec \ = \ \frac{5 \ * \ (400)}{2}$

$Ec \ = \ \frac{2 \ 000}{2}$

$\boxed{Ec \ = \ 1 \ 000 \ J}$

Answer 2

$\sf m=5000\,g$

$\sf m=5\,kg$

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

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

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

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

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

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