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

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

blazeryder · Answer

$$K.E = 0.5 \times m \times v ^{2}$$ 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! =)