1. First, invest in a spare inner tube. If you get a puncture on the road it's far easier to change the tube and repair the punctured one later at home. To repair the tube you'll need a pump, tyre levers and a puncture repair kit with patches, sandpaper, a marker and glue.
Mass is a measure of the number of atoms in an object combined with the density of those atoms. Usually people measure mass in kilograms. You can tell how much mass something has by measuring how hard it is to get that thing to change directions or slow down. If you're driving a big truck, for instance, you're going to need a lot stronger brakes to stop the truck than if you were riding a bicycle.
Mass is defined as the amount of matter an object has. One of the qualities of mass is that it has inertia As an example of inertia, imagine an ice puck resting on a frozen pond. It takes a certain amount of force to set the puck in motion. The greater the mass the more force will be needed to move the puck. The same is true if the puck were sliding along the ice.