Question

A boulder is launched from the ground by a catapult with a vertical velocity of 13.0 m/s and a horizontal velocity of 15.0 m/s. It misses the enemy castle and hits the ground. How long did it take the boulder to hit enemy ground? (ignore air friction)

A 0.38 s
B 2.65 s
C 0.75 s
D 1.33 s

Answer 1

step by step.. find the initial speed of the boulder which is just the resultant component of both forces using Pythagoras theorem.

Answer 2

wait so how would u do that?

Answer 3

X= sqrt(13^2 + 15^2)

Answer 4

and then?

Answer 5

lol.. answer is B.. you dont have to find the resultant component since theres no angle.. sorry :( if you have the vertical component of the velocity, then just use********* time= 2v/g its kind of a long derivation though.. U r supposed to get 2.6503

Answer 6

where v=13

Answer 7

how do u know u dont use 15?

Answer 8

it is not travelling horizontally right? so the components are independent of each other.. ig you were to plug in the value for the horizontal component, then the answer would be wrong.. the resultant velocity will give you a larger answer..

Answer 9

oh okay that makes sense! thanks!