Given that your childs weight is 50 Ibf 222 N and the Power

Given that your child\'s weight is 50 Ibf (222 N) and the Power Wheels Wild Thing^TM also weighs 222N, and that the Wild Thing^TM tires are 30.5 cm diameter, and that the 12 V battery has a capacity of 9 A-hr you can determine the maximum distance traveled on a single battery chaise. Report your answer in meters. Do so by assuming that there are no frictional, resistive, or other losses and that the battery/electric motor combination produces exactly the torque required to move your child in the Wild Thing^TM forward. You may assume that the coefficient of friction between the ground and wheels is 1.

Solution

ANS:3.78 Kilometers

the vehicle is run by an electric motor.

average walking speed of humans is 6 km / hour. so assume the vehicle also moves in that speed.

6 km = 6000 meters: dia of wheel = .305 meters: therefore rpm = 6000m/.305m/60mins = 327 rpm (wheel and motor)

torque= force * radius : 444N* .0125 m = 5NM (torque)

power of motor = (2*pi*N*T)/60

substitute t=5NM; N= 327 rpm

Power = 171 WATTS

total power of battery =V*I : 12v *9ah = 108 Watts

total stand by time = 108/171 = 0.63 hours

distance crossed in 1 hr = 6 km : there fore distance crossed in 0.63 hours is 3.78 hours

ANS:3.78 Kilometers