what is the mass of a vehicle traveling at 25 km/hr with a kinetic energy equal to 1 x 10 to the 4th power J?

Answer 1

V = 25km/h = 25000m/3600s = 6.94 m/s.

KE = 0.5m*V^2 = 10^4 J.
0.5m*6.94^2 = 10000
24.08m = 10000
m = 415.3 kg.