What You Need to Know About the Natural Laws of Driving
All drivers should be aware of the natural laws of physics that affect any moving or stationary object.
While the rules of the road are of utmost importance to know and obey, understanding the natural laws of driving will help you be able to anticipate how your vehicle handles and reacts in various situations and instills confidence behind the wheel. Here we will go over some tips and tricks of controlling your vehicle against the natural laws of driving.
What Are the Natural Laws of Driving?
Gravity: the force that pulls all objects towards the center of the Earth. Everyone and everything experiences gravity and it has a major effect on your vehicle when driving uphill or downhill.
- When you are driving uphill gravity is working against you, meaning that it is pulling your vehicle in the opposite direction. You need to use more engine power in order to reach the top of the hill and to maintain the speed limit.
- When driving downhill, gravity will push your vehicle forward causing it to accelerate. It is a good idea to push your brakes gradually and slowly in order to slow down safely and to maintain control of your vehicle.
Inertia: The law of inertia states that:
- Object at rest tend to stay at rest
- Objects in motion tend to stay in motion at the same speed and direction
- Objects may change their motion only if influenced by an unbalanced force
The law of inertia applies to your vehicle as well as objects inside of it. A car will continue to move unless it is slowed down or stopped by another force — whether it be the brakes or an obstruction. So if, for example, you are driving 55mph, every object in the car is also moving 55mph; if the car hits a wall, all objects in the vehicle still move at 55mph — hence the importance of seatbelts, air bags and other safety features. For this reason, it is important to keep loose items secured inside of the vehicle.
Potential Energy: the energy that is stored in an object. The most common type of potential energy is when an object has the potential to “fall” or be pulled towards the center of the earth due to gravity. For example, when you park your car at the top of a hill, it has potential energy as gravity is pulling your car downward.
Kinetic Energy: the energy that is caused by motion. The kinetic energy of an object is the energy or force that the object has due to its motion. For example, a moving vehicle has kinetic energy and as you increase the speed of the vehicle, the kinetic energy of the vehicle increases as well. The more kinetic energy your vehicle has, the more effort required to stop the vehicle.
Friction: a force that is caused by the contact of one surface on another. When driving, keep in mind that friction is:
- Increased by the weight of your vehicle
- Decreased if your tires are over-inflated or under-inflated
- Decreased if your tires are worn smooth
- Affected by the material and condition of the road
Centrifugal and Centripetal Forces: these forces work opposite of each other and affect objects traveling on a curved path and will affect the way your vehicle behaves on the road. In order to understand these forces, imagine that any curve you drive on as part of a complete circle. The centripetal force pulls your vehicle to the center of the circle, while the centrifugal force pulls it away from the center. It is important to be aware of these forces when driving on a curved road and to find a balance between understeering (not turning the wheel enough) and oversteering (turning the wheel too much).
Momentum: the force that exists in a moving object. The momentum of an object is proportional to its weight and speed. When you are driving, you and your vehicle have obtained momentum that is based on the total weight of your vehicle and the speed at which you are driving. When slowing down or stopping your vehicle you must decrease the momentum of your vehicle by:
- Using the friction force of your brakes by utilizing your brakes,
- Using the friction force between your tires and the road, which is done automatically
- Using the compression force your engine by switching to a lower gear, if necessary
Importance of Understanding the Natural Laws of Driving
These forces affect how your vehicle works, despite the type or quality of the vehicle and the skills of the driver. While you don’t have to be actively thinking about physics while driving, these laws are important to understand as second nature because it will help you control your vehicle during turns, stops, and other everyday driving situations. Being informed and aware of how natural laws can affect driving can help you be alert to emergency situations and prevent crashes.
Once you gain an understanding of the natural laws of driving you can use your knowledge to:
- Determine how physics applies to your vehicle and be prepared for any situation
- Make safe and smart driving decisions
- Have more control over your vehicle
- Be conscious and aware of hazardous situations
Top Driver Driving Schools Will Prepare You
With more than 40 locations throughout Illinois, Michigan, and Ohio, Top Driver is your best resource for driver education, providing over 21,000 hours of in-vehicle training and 15,000 hours of classes each year. We have a variety of teen programs for new drivers, adult refresher courses, and remedial courses.
Top Driver is also going the extra mile to ensure a safe learning space for our students and instructors by providing remote classroom education opportunities and implementing a coronavirus vehicle sanitization process.
Call 1 (800) 374-8373 or enroll online today!
Additional Reading:
- What Should Be in Your Vehicle if Your Car Breaks Down?
- Everything You Need to know About REAL ID in Illinois
Frequently asked questions
How does gravity affect my vehicle on hills?
Gravity pulls everything toward the center of the Earth, and your vehicle is no exception. Driving uphill, gravity works against you, so you need more engine power to maintain speed. Downhill, gravity accelerates the car for you, which means you have to use the brakes earlier and more gradually to stay in control. Slamming the brakes on a long downgrade can overheat them and cause brake fade. A better approach is engine braking by downshifting, combined with light, steady brake application. Trucks lose control on steep grades for exactly this reason.
What is the law of inertia and why does it matter when driving?
Inertia means an object at rest stays at rest and an object in motion stays in motion at the same speed and direction until acted on by an outside force. For drivers, this is why seatbelts and airbags exist. If your car is moving at 55 mph and hits something, every loose object inside, including unrestrained passengers, continues at 55 mph until something stops them. That's also why you should secure cargo. A water bottle, laptop, or grocery bag becomes a projectile in a sudden stop. Inertia is also why your stopping distance grows with speed.
What's the difference between kinetic energy and potential energy in driving?
Potential energy is stored energy waiting to be released, like a car parked at the top of a hill that gravity could pull downward. Kinetic energy is the energy of motion, and a moving car has plenty of it. The faster you go, the more kinetic energy your vehicle carries, and that energy has to be removed before you can stop. Doubling your speed quadruples your kinetic energy, which is why stopping distance grows so quickly above highway speeds. Understanding this is why we coach students to anticipate stops well in advance instead of braking late.
How does friction affect driving and how do I keep good traction?
Friction is the grip between your tires and the road, and it's what lets you accelerate, brake, and steer. Friction increases with the weight of your vehicle and decreases when tires are worn smooth, over-inflated, or under-inflated. Road conditions also matter. Wet, icy, snowy, or oily pavement reduces friction sharply. To maintain traction, keep tires properly inflated, replace them before tread wears down to the wear bars, and adjust speed for surface conditions. Smooth steering and braking inputs preserve grip. Sudden jabs at the wheel or pedals can break it.
What are centripetal and centrifugal forces and how do they affect cornering?
When you drive through a curve, imagine that curve as part of a complete circle. Centripetal force pulls your vehicle toward the center of that circle, which is what keeps you on the curved path. Centrifugal force feels like it pushes you outward, away from the center, which is why you're pressed against the door in a tight turn. The faster you take a curve, the stronger both forces become. The skill is finding the balance between understeering (not turning enough, drifting wide) and oversteering (turning too much, swinging the rear out). Slowing before the curve and steering smoothly through it keeps both forces manageable.
How do I stop a moving vehicle most effectively given the laws of physics?
You're working against momentum, which is the combination of your vehicle's weight and speed. Three forces help reduce that momentum: brake friction when you press the pedal, tire-to-road friction (which happens automatically), and engine compression when you downshift to a lower gear. On normal stops, gradual brake application uses all three smoothly. In an emergency, firm steady pressure on modern anti-lock brakes is most effective. On long downhills or with heavy loads, downshifting takes load off the brakes and prevents them from overheating. Anticipating stops earlier always gives you more options than reacting at the last moment.
Why do Top Driver instructors teach physics as part of driver education?
Because the rules of physics don't care how new or experienced you are. Whether you're driving a compact car or a full-size SUV, gravity, inertia, friction, kinetic energy, and momentum behave the same way. When new drivers understand these forces, they make better decisions about speed before curves, following distance, lane position on hills, and braking technique. Top Driver operates more than 40 locations across Illinois, Michigan, and Ohio and provides over 21,000 hours of in-vehicle training and 15,000 hours of classroom instruction each year, with physics woven into the curriculum so students develop intuition for how their car will behave.
