# A piece of wood of mass 0.03 kg is dropped from the top of a mass 0.02 kg is fired vertically upward, with a velocity 100 , from the ground. The bullet gets embedded in the wood. Then the maximum height to which the combined system reaches above the top of the building before falling below is : (g=10 ) (a) 30m (b) 10m (c) 40m (d) 20m

## Question ID - 50231 | SaraNextGen Answer A piece of wood of mass 0.03 kg is dropped from the top of a mass 0.02 kg is fired vertically upward, with a velocity 100 , from the ground. The bullet gets embedded in the wood. Then the maximum height to which the combined system reaches above the top of the building before falling below is : (g=10 ) (a) 30m (b) 10m (c) 40m (d) 20m

3537

Time taken for the particles to collide,

T= = =1sec

Speed of wood just before collision=gt=10m/s & and speed of bullet just before collision v−gt =100−10=90 m/s

Now, conservation of linear momentum just before and after the collision

(0.02) (1v) + (0.02) (9v)= (0.05)v

⇒150 = 5v

⇒ v = 30m/s

Max. height reached by body h=

h= =45m

Height above tower =40m