Question

A drone is flying horizontally when it runs out of battery and begins to free fall from 20m. No drag. If it lands 60m away (in the x-direction) from where it began to fall, what was it's horizontal velocity while it fell

Answer 1

Step-by-step explanation:

Remark

At the time it takes to drop 20 m is the same time it takes to travel 60 m horizontally.

Givens

h = 20 m

hd = 60 m

g = 9.81

vi = 0

Formula

d = vi*t + 1/2 a * t^2 We are solving for t

Solution

When the battery fails, the vertical initial velocity is 0. So we have to find the time it would take to drop 20 meters

d = 0*t + 1/2 * 9.81 a* t^2

20 = 4.91 * t^2 Divide by 4.91

20/4.91 = 4.91 t^2 / 4.91

4.073 = t^2 Take the square root of both sides.

t = 2.02 seconds

Horizontal

d = 60 m

t = 2.02 seconds

v = ?

Note: there is no horizontal deceleration or acceleration

v = d/t

v = 60/2.02

Answer: v = 29.73 m/s