A ballis thrown upward with an initial velocity of 100ms^(-1). After how much time will it return? Draw velocity - time graph for the ball and find from the graph (i) the maximum height attained by the ball and (ii) height of the ball after 15 s. Take g=10ms^(-2).

A ballis thrown upward with an initial velocity of 100ms^(-1). After h

1.	A ballis thrown upward with an initial velocity of 100ms^(-1). After how much time will it return? Draw velocity - time graph for the ball and find from the graph (i) the maximum height attained by the ball and (ii) height of the ball after 15 s. Take g=10ms^(-2).
Answer» Solution : Here, `u=100ms^(-1),g=-10ms^(-2)` At HIGHEST point, `v=0` As `v=u+g t therefore 0=100-10xxt` `therefore` Time taken to REACH highest point, `t=(100)/(10)=10s` The BALL will return to the ground at `t=20s` Corresponding VELOCITY - time graph of the ball is shown in (i) Maximum height ATTAINED the ball = Area of `DeltaAOB` `=(1)/(2)xx10xx100=500m` (ii) Height attained after `15s` = Area of `DeltaAOB+` Area of `DeltaBCD` `=500+(1)/(2)(15-10)xx(-50)=500-125=375m`