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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 Top 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

1 Answer
127 votes
Answer Key / Explanation : (c) -

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

127 votes


127