Is racing,javelin are supported by friction?

Racing and javelin throwing can be both supported, as well as hindered by friction.

• Racing

If there was no friction between the tires and the ground in car or bike racing, wheels would just spin and the car or bike would not get enough grip to get a forward motion. Friction also assists in steering a vehicle.

Without enough grip or friction to transmit the sideways motion of the wheel, the forces applied through the speed would simply carry on pushing the vehicle straight forward.

The very same friction, in addition to air friction, also slows down a vehicle to a certain extent. For this very reason pinewood racing drivers do their utmost to reduce friction on their vehicles.

• Javelin

A javelin thrower is assisted by friction in two ways. One is the friction needed to keep a grip on the javelin. Without it, the javelin would simply slip out of the hand. The friction also has to be just right in order to release the javelin smoothly, so it does not just slide out of the hand and into the ground right in front of the thrower.

The second way in which friction supports a javelin thrower is through his foothold. If he does not have enough grip on the ground to stop, he may either injure himself by slipping or go skidding over the line and end up having a foul throw.

Again, it is air-friction which is the hindering part of the action. As the javelin glides through the air, friction slows it down to the point when it will eventually drop down.

This is why javelins are shaped the way they are. The slim, stream-lined body offers the least air resistance, allowing the javelin to keep up speed and consequently stay in the air for longer distances.