You don’t need Sir Isaac Newton to tell you a 4x4 ute will accelerate down a steep slope if the driver doesn’t use suitable braking.

Thankfully, the Mazda BT-50 uses a feature called Hill Descent Control, or HDC. It’s designed for slow-speed off-road driving. At the touch of a button, HDC controls the BT-50's braking system to help you drive down steep and slippery terrain in a controlled manner. It lets you concentrate on the path ahead instead of worrying about how much brake pedal pressure to apply.  

Even Newton would enjoy it. Check out this video.