an aeroplane is travelling horizontally at a speed of 80ms and drops a crate of emergency supplies.To avoid damage,the max vertical speed of the crate on landing is 20ms.

Question

a)calc d max height of the aeroplane when the crate is dropped
b)calc d time taken for the crate to reach the ground from this height.

Answer 1

v = at
20 = 9.8 t
t = 2.04s
so, it can't fall for more than 2.04 seconds, or it will be going too fast

so, how far will it fall in 2.04 s?
s = 1/2 at^2
s = 4.9 * 4.16
s = 20.38m

Man, that's some low flyer!

Answer 2

Shouldn't we like need to find the total velocity first since horizontal speed is 80m/s and vertical speed is 20m/s?

Answer 3

Very helpful

Answer 4

Thank you very much. this was very helpful.

Answer 5

Using V2 = U2 + 2gh
U=0
V2 = 2gh
h = V2/2g
h = 400/19.62
h = 20.39m