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If you watch the film, the section of the freeway they are jumping appears to be flat. It does not look like there is any kind of ramp, an angled surface, to jump off. This is a problem. Why? Because vertical motion and horizontal motion are independent of each other. What does this mean? Let’s look at each one in turn. Vertical Motion: objects falling due to gravity, or aeroplanes rising, overcoming gravity. If we consider an object falling due to gravity, how long would it take to fall a set distance? If an object falls from rest, then it will fall at approximately 10 ms-2, due to the constant pull of the earths gravity. So how fast will it be falling after 5 seconds? If speed = acceleration x time then 10 x 5 = 50 ms-1 or 180km/hr. That is the final vertical speed, but what would the average speed have been? If you are accelerating at a constant rate (and when falling you usually are) then the average speed would be half of the final speed so it will be 25 ms-1 So how far would the object have fallen in 5 seconds? 25 x 5 = 125 metres. Here come the equations!
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