Question

In an action movie, the heroine is supposed to jump with a motorcycle from the roof of one skyscraper to another one. The roof of the second skyscraper is h=11 meters lower, and the gap between the buildings is d=18 meters wide. Both roofs are horizontal and flat. Neglecting air resistance, what minimum initial speed would she need to make the jump?

Answer 1

12m/s

Step-by-step explanation:

So she would need to cover at least 19 m horizontally while falling a distance of 11 m. Since her initial vertical velocity is 0. Gravitational acceleration g = 9.81 m/s2 is the only thing that affect her vertical motion. We can use the following motion equation to calculate the time it takes for her to drop 11m

`h = gt^2/2 = 11`

`t^2 = 2h/g = 2*11/9.81 = 2.243`

`t = √(2.243) = 1.5s`

This is also the time it takes for her to travel 18m horizontally. So we can calculate the horizontal velocity that she needs

v = s / t = 18 / 1.5 = 12 m/s