1- a projectile is fired at an angle 30 degrees above the horizontal from a 20 m
ID: 1329306 • Letter: 1
Question
1- a projectile is fired at an angle 30 degrees above the horizontal from a 20 m high cliff and lands 25 second later at distance from the base of the cliff. Determine the projectile's fiinal velocity just before it hits the ground. use i for the horizontal vector and j for the upward vetical vector.
2- one some planet, an aline throws a ball dierctly upward with a velocity of 50 m/s and cathces it 20 second later. Determine the acceleration of gravity on this planet. Use +j for the downward dirction.
Explanation / Answer
Here ,
1)
let the initial speed of the ball is v
Using second equation of motion
y = u*t + 0.5 at^2
-20 = u * sin(30) * 25 - 0.5 * 9.8 * 25^2
solving for u
u = 243.4 m/s
now , for the final vertical velocity
v^2 - (243.4 * sin(30))^2 = 2 * 9.8 * 20
solving for v
v = 123.3 m/s
hence , the final velocity is
v = 243.3 * cos(30) i - 123.3 j m/s
v = 210.7 i - 123.3 j m/s
the final velcity is (210.7 i - 123.3 j m/s)
------------------------
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.