How to make a shopping cart move with ease without a motor. like if the carts front wheels were smaller than the ones in the back the cart would move forward easier, or if the front of the cart is heavier so when you push it moves better or something like that.

Water in a partially filled large tank is to be supplied to the roof top, which is 8 m above the water level in the tank, through a 2.2-cm-internal-diameter pipe by maintaining a constant air pressure of 300 kpa (gage) in the tank. if the head loss in the piping is 2 m of water, determine the discharge rate of the supply of water to the roof top in liters per second.