A bullet moving with a velocity of 100 m/s can justBulilaccelerationpe

1.	A bullet moving with a velocity of 100 m/s can justBulilaccelerationpenetrate two planks of equal thickness. The number ofsuch planks penetrated by the same bullet, when thevelocity is doubled, will be:(a) 4(c) 8(b) 6(d) 10
Answer» 3rdequation of motion can be be applied:v^2 = u^2 + 2as, where acceleration is -ve. Hence v^2 = u^2 – 2as. v, final velocity = 0. Therefore, u^2 = 2as. i.e. s is proportional to u^2. → s1÷ s2= u1^2 ÷ u2^2 Therefore, s2= (u2^2 ÷ u1^2) x s1= (200÷100)^2 x 2 (planks) = 8 planks Answer is8

A bullet moving with a velocity of 100 m/s can justBulilaccelerationpenetrate two planks of equal thickness. The number ofsuch planks penetrated by the same bullet, when thevelocity is doubled, will be:(a) 4(c) 8(b) 6(d) 10

Answer»

3rdequation of motion can be be applied:v^2 = u^2 + 2as, where acceleration is -ve. Hence v^2 = u^2 – 2as.

v, final velocity = 0. Therefore, u^2 = 2as.

i.e. s is proportional to u^2. → s1÷ s2= u1^2 ÷ u2^2

Therefore, s2= (u2^2 ÷ u1^2) x s1= (200÷100)^2 x 2 (planks) = 8 planks

Answer is8

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A bullet moving with a velocity of 100 m/s can justBulilaccelerationpenetrate two planks of equal thickness. The number ofsuch planks penetrated by the same bullet, when thevelocity is doubled, will be:(a) 4(c) 8(b) 6(d) 10

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