# What are examples of inertia of direction?

The concept of inertia refers to the resistance of any physical object to any change in its state of motion, including changes to its speed and direction. “Inertia of direction” isn’t a standard term in physics, but if we consider it to mean the tendency of an object to continue moving in its current direction unless acted upon by an external force, there are many examples we can think of:

1. Spacecraft in Space: Once a spacecraft is moving in space, far from any significant gravitational pull, it will continue in the same direction at a constant speed indefinitely. This is because there is very little external force (like air resistance) to change its direction.

2. Skater on Ice: If you’ve ever watched ice skating or played hockey, you’ll know that when a skater pushes off, they continue moving in the same direction until they either turn, stop themselves, or are stopped by an external force like friction or a collision.

3. Car on a Slippery Road: If a car is moving on an icy or very slippery road and the driver tries to turn suddenly, the car might not turn as expected because its tires can’t grip the surface well. This is due to the car’s inertia, wanting to keep it moving in the original direction.

4. Rowing a Boat: When you stop rowing in a boat, it doesn’t stop immediately but continues to move forward due to its inertia.

5. Playing Billiards or Pool: When you strike a ball, it will move in the direction you hit it. If there’s no obstacle in its path, it’ll continue in that direction because of its inertia until friction with the table or a collision with another ball changes its motion.

6. Spinning Frisbee: Once you throw a frisbee, it will generally continue in the direction you threw it (though it might curve due to its spin and air resistance). The initial direction it maintains is due to its inertia.

In each of these examples, the key element is the object’s tendency to continue moving in its original direction until some force causes it to do otherwise.