Question #189b5 Physics 1D Motion Displacement and Velocity 1 Answer P dilip_k Feb 22, 2017 Let downward initial velocity of the pebble be #u# So utilising #h=uxxt+1/2xxgxxt^2# we get #91.2=uxx4+1/2xx9.8xx4^2# #=>4u=91.2-8xx9.8# #=>u=91.2/4-8xx9.8/4# #=>u=22.8-19.6=3.2"m/s"# Answer link Related questions What is the difference between distance and displacement? Is displacement directly proportional to velocity? How does average velocity differ from instantaneous velocity? How can I calculate the change of velocity? How do speed and velocity differ from each other? How do velocity and acceleration differ? How do displacement and distance differ? Can displacement be negative? Can velocity be zero if accelerating? Explain why displacement is a vector quantity? See all questions in Displacement and Velocity Impact of this question 1090 views around the world You can reuse this answer Creative Commons License