Astudent walks 10meters east down a hallway before realizing she has dropped a book. she turns around and walks 3meters west to pick it up. she then turns back around and walks 8 more meters east to her classroom. what is the total distance? what is the total displacement? if in it out! the total distance traveled is 8 m her displacement was 10 m east the total distance traveled is 15 m her displacement was 3 m east the total distance traveled is 10 m her displacement was 15 m east the total distance traveled is 21 m her displacement was 15 m east

the velocity you are looking for is made up of two parts: horizontally velocity, vh, and its vertical velocity, vv. the actual velocity of the ball will be these two parts added together, and because velocity is a vector then they will need to be added vectorially.  

neglecting air resistance etc etc.,  

the horizontal velocity component will be constant (because there is no accelerating force in the horizontal direction.  

vh = 8 ms-1  

the vertical velocity component has an accelerating force: 'g'.  

using v = u +at where a = g = 9.81 ms-2.  

the vertical component of velocity, vv = 0 + gt = vv =9.81 x 2  

vv = 19.62 ms-1 . the zero appears because the virtical component of velocity at time t=0 is zero. remember, the ball was thrown horizontally.  

how fast it will be moving (it actual path (being a parabola )) will be the vector sum of these two.  

adding vectorally gives: -  

v = sqr root (8^2 + 19.62^2) = sqr root(64+384.9) = 21.18 or 21.2 ms-1