A ball is thrown downwards with a speed of 20m//s from top of a building 150m high and simultaneously another ball is thrown vertically upwards with a speed of 30m//s from the foot of the building . Find the time when both the balls will meet . (g=10m//s^(2))

A ball is thrown downwards with a speed of 20m//s from top of a buildi

1.	A ball is thrown downwards with a speed of 20m//s from top of a building 150m high and simultaneously another ball is thrown vertically upwards with a speed of 30m//s from the foot of the building . Find the time when both the balls will meet . (g=10m//s^(2))
Answer» <html><body><p></p>Solution :(i)`S_(1)=20t+5t^(2)+S_(2)=30t-5t^(2)`<br/>`150=50t`<br/>`t=3s`.<br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_ELT_AI_PHY_XI_V01_A_C03_SLV_026_S01.png" width="80%"/><br/>(<a href="https://interviewquestions.tuteehub.com/tag/ii-1036832" style="font-weight:bold;" target="_blank" title="Click to know more about II">II</a>)<a href="https://interviewquestions.tuteehub.com/tag/relative-1183377" style="font-weight:bold;" target="_blank" title="Click to know more about RELATIVE">RELATIVE</a> acceleration of both is zero since both have acceleration in <a href="https://interviewquestions.tuteehub.com/tag/downward-2061463" style="font-weight:bold;" target="_blank" title="Click to know more about DOWNWARD">DOWNWARD</a> direction.<br/>`veca_(AB)=veca_(A)-veca_(B)=g-g=0`<br/> `vecV_(BA)=30-(-20)=<a href="https://interviewquestions.tuteehub.com/tag/50-322056" style="font-weight:bold;" target="_blank" title="Click to know more about 50">50</a>`<br/>`S_(BA)=V_(BA)xxt`<br/> `t=(S_(BA))/(V_(BA))=(150)/(50)=3s`<br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/AKS_ELT_AI_PHY_XI_V01_A_C03_SLV_026_S02.png" width="80%"/></body></html>