Gravity is the force pulls objects towards the centre of the earth.
It gives objects their weight and keeps them in contact with the ground
When driving uphill or downhill, you need to compensate for the change in affect that gravity is having on your vehicle by either applying the brakes or the accelerator.
The steeper the grade (hill), the greater the effect that gravity will have on your vehicle.
The steeper the uphill grade, the slower you will go
When driving uphill, choose the appropriate gear that will provide necessary climbing power and maintain your speed by increasing pressure on the gas pedal
Stopping distance while going uphill is much shorter than on a flat or downhill.
The steeper the downhill grade, the faster you will go
When driving downhill, check the brakes by applying a slight pressure.
Release the gas pedal to take advantage of engine compression for slowing you down.
Stopping distance while going downhill is much longer than on a flat or uphill.
Centre of Gravity
The point around which all of your vehicle weight is centred.
Modern vehicles have a low centre of gravity, giving them excellent road-handling characteristics
Vehicles with more weight up high (trucks, jeeps, four-wheel-drive vehicles, cars with roof racks) have a higher centre of gravity.
The higher the centre of gravity the higher the risk for rollover.