History Window Help session.masteringpnysies com ng 2015, PHYS 1111/1113, Sectio
ID: 1263980 • Letter: H
Question
Explanation / Answer
Lets assume the mass of baseball = m
height of baseball = h
speed of launch = V
final speed before hitting the ground = Vf
Potential energy of ball = mgh
Kinetic energy at the instant of launching = (0.5) m V2
Kinetic energy at the instant before hitting ground = (0.5) m Vf2
Using conservation of energy :
Potential energy of ball + Kinetic energy at the instant of launching = Kinetic energy at the instant before hitting ground
mgh + (0.5) m V2 = (0.5) m Vf2
Vf2 = V2 + 2gh
from this we see that , speed does not depend on how the ball is thrown
So speed remains same all the cases.