Apr 2022

G-forces: A Brief Overview Of This Physics Phenomena

April 11, 2022

G-forces: A Brief Overview Of This Physics Phenomena

For those that have been on a rollercoaster ride at least once in their lives, the feeling of your gut trying to climb upwards whilst your eyeballs are being pushed back into your head are undoubtedly some of the common experiences from the ride. This occurs due to a few forces that come into play: the Earth’s gravity.

Since the planet possesses a substantial amount of mass, it naturally has a large gravitational field, resulting in the constant pulling that tethers everyone and everything to the ground. But when people make sharp turns such as those in rollercoasters, slamming the brakes of their car, or taking off in a jet to space – they are tossed and turned by forces much stronger than this ever-present gravity. So, why does this occur?

Understanding g-forces

Engineers label these other forces as g-forces, which have varying numbers according to how intense they are. The force that the Earth’s natural gravity exerts on us when standing still is numbered at 1 g. Each particle that comprises the planet is pulling on everything at the same time. Alone, those pulls are weak, but they become powerful enough to keep you on the ground when combined. In comparison, race drivers experience 5 gs when accelerating in their vehicles, which is 5 times more intense.

Whenever objects change their velocity quicker than gravity, the forces they feel will surpass 1 g. Weightlessness associated with being in space is labelled as 0 g. The other extreme, which is 100 gs, would mean certain death since such forces are sufficiently intense to pulverise bones and squish organs in the body.

As you may have already guessed, g-forces come from many other sources besides gravity. They occur whenever vehicles, such as cars or planes, suddenly shift their velocity, whether speeding up, slowing down, or making a sharp turn. The quicker these actions happen, the more force is experienced.

How to measure g-forces

If you are curious to know the amount of gs you experience during intense accelerations, you can take your max speed first. Afterwards, divide it by the amount of time taken to reach that speed, then further divide it by 9.81 m/s2. The result is the number of gs you have experienced.

As an example, imagine yourself behind the steering wheel of one of the fastest supercars to date, the Bugatti Veyron, while accelerating. For the formula, 100kph gets converted to 28m/s. With all the data available, we now get the following:

28m/s / 2.3 seconds = 12 m/s2

12m/s2 / 9.8 m/s2 = 1.2 gs

Intense acceleration can result in loss of consciousness

Air Force pilots who take sharp turns when riding their jets will experience blood rushing down into their lower bodies. This happens because as the aircraft turns, the body’s fluids act as if they are in a centrifuge and move towards whichever part of the body is on the outermost edge of the turn.

Once that occurs, your organs, such as the eyes, will not get enough oxygen and suffer a grey out, a phenomenon wherein there is an instant loss of colour in one’s vision or, at worst, a total blackout and temporary blindness. Accelerating harder will lead to more dire results, like a complete loss of consciousness since the blood fully retreats from the brain, resulting in oxygen deprivation.

When it comes to the effects of g-forces, not everyone is the same. Some may feel it even well below 5 g, but others who are trained to increase their resistance threshold, such as veteran fighter pilots, are capable of handling more than the average person since they are physically fit. Combined with resistance training and specialised suits made to squeeze blood back up to the head, their tolerance towards the effects of g forces improves.


Out of all the forces that act on the human body, g-forces certainly rank among the top of those which have fascinating consequences. If you are keen on learning more about the details of their occurrence, along with other exciting physics phenomena, consider signing up for physics tuition today! Suppose you are interested in exploring the inner workings of the scientific realm or delving deeper into specific physics topics. In that case, it is advised that you seek proper guidance from a reputable physics tutor.

At Best Physics Tuition™ Centre, our O level and JC H2 physics tuition classes are guaranteed to equip you with the knowledge you need to excel in the subject. Sign up for our lessons today and get your learning on as soon as possible!

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