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Grade 11Mechanics

An open lift is moving upwards with velocity 10m/s.it has an upward acceleration of 2m/s. A ball is projected upwards with velocity 20m/s relative to ground.Find (a)time when ball again meets the lift

Question image for An open lift is moving upwards with velocity 10m/s
Profile image of Himanshu Mane
8 Years agoGrade 11
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1 Answer

Profile image of Arun
8 Years ago
Dear Himanshu
 
We can combine x = v(initial)*t + .5*a*t^2 
v(initial ball)*t + .5*a*t^2 = v(initial lift)*t + .5*a*t^2 
20t + .5(-9.8)(t^2) = 10t + .5(2)(t^2) 
10t - 4.9t^2 = t^2 
0 = 5.9t^2 -10t 
t = 1.695s