The force of gravity that pulls you downwards towards the centre of the earth would cause you to accelerate if the ground weren't in the way. This means your speed would increase, with every second that passes. The value of the acceleration due to gravity is 9.8 m/s2, or 9.8 metres per second per second. In other words, as you fall, your speed will increase by 9.8 m/s for every second that you fall. Some rides are designed to let you fall with a smaller acceleration, so that you don't get injured. From the height of a roller coaster, for example, you would be moving way too fast at the bottom if the drop were nearly vertical and there were no breaking... the ride would be over too soon, you wouldn't experience the same sense of speed (it would be over too fast), and you might be injured as the ride levelled out. Designers slow the acceleration by making a ramp. The angle of the ramp determines what the acceleration will be ... the larger the angle, the closer the value will be to 9.8 m/s2 You can actually calculate the acceleration down the ramp by using some trigonometry. This calculation comes from Math 9 and Math 10C; the topic of acceleration vectors itself is from Physics 20. Here's the same picture, showing the two values. The ordinary acceleration due to gravity, if you were falling straight down, would be 9.8 m/s2 However, the ramp causes you to fall at an angle. The ramp's angle is 55°, which results in an acceleration doen the ramp of only 8.0 m/s2 The length of the ramp is then designed to give the desired (and safe) final speed at the bottom. The question now is where did the 8.0 come from. Let's look at the calculation: Examine this diagram closely. Notice the angle of 55° at the bottom of the ramp. The acceleration vector 9.8 is drawn at a point on the ramp, and its component down the ramp, X. We want to find X. In order to solve for X, which is the acceleration down the ramp, we need an angle in the small triangle. The bottom one turns out to be 55° also ... here's why: Angles 'a' and 'b' are equal because of the parallel lines. But the sum of the angles in the big right triangle must be 180°, so 'a', and hence also 'b', must be 45°. In the small right triangle, this makes the lower angle 55. Using a simple trigonometric function, the sine, we can calculate the value of X. It turns out to be 8.0 Amusement Park Physics