5. Katie left her 40 Watts light bulbs on in her room for 24 hours a day for the entire month of April. Calculate the total cost of energy if the average rate of electricity is 15 cents per k Wh. [2K] 6. A 150 N horizontal force moves a 120.0-kg crate on a frictionless ice from rest to a final speed of 6.0 m/s. Use the work energy theorem to calculate the displacement of the crate at the time it reaches this speed. [3A]7. An electric car's engine is only 35% efficient at converting electric energy to to mechanical energy. If it takes 150,000J the electric energy to increase the speed from zero, what is its final speed given the mass of the car is 2500 kg. [3A]