Question

calcule a energia cinética de um corpo de massa 10kg no instante que sua velocidade e 72km\h.

Answer 1

$\Large{\begin{array}{l}\tt Convers\tilde{a}o\,km/h~para~m/s\, dividir\,por\,3,6.\\\tt \dfrac{72\,km/h}{3,6}=20\,m/s\\\tt Aplicando\,a\, f\acute{o}rmula\, temos:\\\tt E_c=\dfrac{m\cdot v^2}{2}\\\ \\ \tt E_c=\dfrac{10\cdot20^2}{2} \\ \\\tt E_c=\dfrac{10\cdot400}{2} \\ \\\tt E_c=\dfrac{4000}{2} \\ \\\boxed{\boxed{\tt E_c=2000\,J}}\end{array}}$