Question

how to do this A young vandal wishes to hit a truck traveling at a constant speed of 20m/s with a water balloon. If the vandal is in a tree, 40 m from the top of the truck, how far should the truck be from the tree when she releases the balloon so that it hits the truck when it is at a position directly beneath her?

Answer 1

Answer:

6.89 m

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

$s=ut+\frac{1}{2}at^2\\\Rightarrow 40=0\times t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{40\times 2}{9.81}}\\\Rightarrow t=2.9\ s$

The water balloon will take 2.9 seconds to hit the tree

As, the truck is moving at a constant speed of 20 m/s it does not have acceleration

$s=ut+\frac{1}{2}at^2\\\Rightarrow s=20\times 2.9+\frac{1}{2}\times 0\times t^2\\\Rightarrow s=6.89\ m$

The boy has to release the balloon when the truck is 6.89 m away