A-horizontal-force-of-0-8N-is-required-to-pull-a-5kg-block-across-a-table-top-at-a-constant-speed-With-the-block-initially-at-rest-a-20g-bullet-fired-horizontally-into-the-block-to-slide-1-5m-before-

Question Number 29216 by NECx last updated on 05/Feb/18

A h o r i z o n t a l f o r c e o f 0.8 N i s

r e q u i r e d t o p u l l a 5 k g b l o c k a c r o s s

a t a b l e t o p a t a c o n s t a n t s p e e d .

W i t h t h e b l o c k i n i t i a l l y a t r e s t, a

20 g b u l l e t f i r e d h o r i z o n t a l l y i n t o

t h e b l o c k t o s l i d e 1.5 m b e f o r e

c o m i n g t o r e s t a g a i n . D e t e r m i n e

t h e s p e e d v o f t h e b u l l e t, w h e r e

t h e b u l l e t i s a s s u m e d t o b e

e m b e d d e d i n t h e b l o c k .

Answered by ajfour last updated on 05/Feb/18

f = 0.8 = 50 μ \Rightarrow μ = 0.016

m v = (M + m) V

μ (M + m) g s = \frac{1}{2} (M + m) V^{2}

\Rightarrow V = \sqrt{2 μ g s}

v = \frac{(M + m) V}{m} = (\frac{M}{m} + 1) \sqrt{2 μ g s}

= (251) \sqrt{2 \times 0.016 \times 10 \times 1.5}

\Rightarrow v = 251 \times \sqrt{48} m / s

= 251 \times 7 (1 - 0.02)

= 1757 - 35 = 1722 m / s .

Facebook Tweet Pin