Suggest a Form of renewable energy that could be used to power an electric ticket machine that only needs to work during daylight hours

The 10-kg double wheel with radius of gyration of 125mm about o is connected to the spring of stiffness k = 600 n/m by a cord which is wrapped securely around the inner hub. if the wheel is released from rest on the incline with the spring stretched 225 mm, calculate the maximum velocity v of its center o during the ensuing motion. the wheel rolls without slipping

Which statement is true? a) the work done to lift an object 6 meters is greater than the gravitational potential energy it gains. b) the work required to push an object is less than the work required to pull an object the same distance. c) the work required to raise an object to a height is equal to the gravitational potential energy the object gains. d) the work done against gravity to lift an object straight up is greater than the work required to roll it up a ramp.

Only 3% of the water on earth is usable by humans. even though that 3% is through the water cycle, we still need to be careful not to waste water.