Question

a car moving with a velocity of 20 meters/second has 1.8 x 10^5 joules of kinetic energy. what is the mass of the car?
4.6 x 10^2 kilograms
9.0 x 10^2 kilograms
1.0 x 10^3 kilograms
1.2 x 10^3 kilograms

Answer 1

\[K.E = 0.5 \times m \times v ^{2}\] rewrite to solve for m\[m={\frac{ 2 \times K.E. }{ v ^{2} }}\]Plug in variable and solve: \[m=\frac{ 2 \times 180000 }{ 20^{2} }\]\[m=\frac{ 360000 }{ 400 }\]\[m=900\] or \[9.0 \times 10^{2}kg\] I hope this helps! =)