A tennis ball rolls off the edge of a table top 0.750m above the floor and strikes the floor at a point 1.40m horizontally from the edge of the table. Ignore air resistance

tennis-ball

#1

A tennis ball rolls off the edge of a table top 0.750m above the floor and strikes the floor at a point 1.40m horizontally from the edge of the table. Ignore air resistance.
a) Find the time of flight.
b) Find the magnitude of the initial velocity.
c) Find the magnitude and direction of the velocity of the ball just before it strikes the floor.

Answer:

Total distance covered vertically is 0.70 and horizontally 1.40/
Time of flight (as it rolled so velocity in y direction initially is zero and let it be v in x direction). S=0.5at*t (For y axis, here S= 0.70 and a=accleration due to gravity). You will find time of flight and now apply S=ut (for x axis,acceleration is 0 in x axis). Use time of flight solved previously and calculate intial velocity which will be onlt horizontal.Now for third use v= u + at separately for x and y axis and find the respective velocities and then you can calculate its magnitude and directon.