A) 20m
B) 48m
C) 26m
D) 12m
Correct Answer: C
Solution :
From Newtons law F = ma where m is mass and a the acceleration. Given, F = 4 N, m = 2 kg \[\therefore \] \[a=\frac{F}{m}=\frac{4}{2}=2\,m{{s}^{-2}}\] Also, distance covered by body is \[d=4\times 5=20\,m\] From equation of motion, displacement (y) is given by \[y=ut+\frac{1}{2}a{{t}^{2}}\] Given, u = 0; \[a=2\,m{{s}^{-2}},\,\,\,t=4\,s\] \[\therefore \] \[y=0+\frac{1}{2}\times 2\times {{(4)}^{2}}=16\,\,m\] In vector form, displacement is given by \[s=x\,\hat{i}+y\,\hat{j}\] \[s=20\,\hat{i}+16\,\hat{j}\] Hence, distance from 0 is \[\left| s \right|=\sqrt{{{20}^{2}}+{{16}^{2}}}\] \[\left| s \right|=\sqrt{400+256}\] \[\left| s \right|=25.6\,m\] \[\Rightarrow \] \[s\approx 26\,\,m\]You need to login to perform this action.
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