A car is on cruise control at v=30m/s. If the wind resistance is equal to. F=0.42v² what energy will the car expend to drive 1km? A)450J
B)378J
C)12.6J
D)378kJ

show your work please

If the speed of a particle triples ,by what factor does its kinetic energy increase?

What would be the strength of earth's gravitational field at a point where an 80.0 kg astronaut would experience a 80% reduction in weight

Aspring is used to stop a 50-kg package which is moving down a 20º incline. the spring has a constant k = 30 kn/m and is held by cables so that it is initially compressed 50 mm. knowing that the velocity of the package is 2 m/s when it is 8 m from the spring and neglecting friction, determine the maximum additional deformation of the spring in bringing the package to rest.