what is the kinetic energy of a van that has a mass of 4200kg and is moving at 40m/s ?
+26387 what is the kinetic energy of a van that has a mass of 4200kg and is moving at 40m/s ?
\(\begin{array}{cll} E_k = \frac12 \cdot m \cdot v^2 \\ \text{where }~ m = \text{ mass of object} \\ v = \text{ speed of object} \\\\ 1\ \text{ Joule } = 1\ kg \cdot \frac{ m^2 } { s^2 } \end{array}\)
\(\begin{array}{rcl} E_k &=& \frac12 \cdot m \cdot v^2 \qquad & m = 4200\ kg \qquad v = 40\ \frac{m}{s} \\ E_k &=& \frac12 \cdot 4200\ kg \cdot ( 40\ \frac{m}{s} )^2 \\ E_k &=& \frac12 \cdot 4200 \cdot 40^2 \frac{kg\cdot m^2}{s^2} \\ E_k &=& 3360000\ \text{ Joule } \\ E_k &=& 3360\ \text{ kJ } \\ E_k &=& 3.360\ \text{ MJ } \end{array}\)
