A large block of wood of mass M = 5.99 kg is hanging from two long massless cords. A bullet of mass m = 10 g is fired into the block and gets embedded in it. The (block + bullet) then swing upwards, their centre of mass rising a vertical distance h = 9.8 cm before the (block + bullet) pendulum comes momentarily to rest at the end of its arc. The speed of the bullet just before collision is: (take g = 9.8ms?²)
A large block of wood of mass M = 5.99 kg is hanging from two long massless cords. A bullet of mass m = 10 g is fired into the block and gets embedded in it. The (block + bullet) then swing upwards, their centre of mass rising a vertical distance h = 9.8 cm before the (block + bullet) pendulum comes momentarily to rest at the end of its arc. The speed of the bullet just before collision is: (take g = 9.8ms?²)
Option 1 -
821.4 m/s
Option 2 -
811.4 m/s
Option 3 -
831.4 m/s
Option 4 -
841.4 m/s
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1 Answer
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Correct Option - 3
Detailed Solution:Using conservation of linear momentum, we can write
P? = P? ⇒ mv = (M+m)V
Using conservation of Mechanical energy, we can write
½ (M+m)V² = (M+m)gh ⇒ V = √2gh
⇒ v = (M+m)/m)√2gh
= (6/0.01)√ (2×9.8×0.098) = 600 × 1.386 = 831.4 m/s
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