A 0.246 kg toy car is powered by one D cell (1.50 V) connected directly to a small DC motor. The car has an effective energy conversion efficiency of 30.6 % , meaning that 30.6 % of the electric energy applied to the motor is converted into translational kinetic energy. After 7.88 s , the car, which is initially at rest, reaches a speed of 2.89 m / s . What is the average current supplied to the car's motor?

Consider a one meter long horizontal pipe with a constant 100 cm^2 cross sectional area. water flows rightward into the pipe at x = 0 with flow velocity 02m/sec at every point within the pipe intake area. at x=1, the rightward flow rate is 0.192 m/sec. assume the water is a conserved quantity in the pipe, so there must be a leak (a sink) somewhere in the pipe. 1. compute net volumetric flow of the source if the system to be in equilibrium. 2. now assume the pipe in the problem has no leaks. compute the net volumetric rate of change for the system.