Motion in a Straight Line

A bullet is fired into a fixed target loses one third of its velocity after travelling 4 cm. It penetrates further D 10-3 m before coming to rest. The value of D is :

1. 2
2. 5
3. 3
4. 4

Answer

BONUS

Solution

Uniform retardation a; v2=u2-2as

First 4 cm (u 2u3): u2- 4u29= 5u29=2a(4) ...(1)

Next x ( 2u3 0): 4u29=2a x ...(2)

(2) ÷ (1): x4= 45 x=3.2 cm

=32 10-3 m D=32

D = 32 is not among the options (2, 5, 3, 4), no option is correct question dropped

Answer: Bonus (full marks to all who attempted)