Question

17. A body of mass 1 kg is moving with velocity
V; = (i - 2j - 3Â) m/s and after 10 s velocity of
body becomes vf= (-3i +2j - k) m/s. The
magnitude of change in momentum of the body
(1) 4 kg m/s
(3) 4√3 kg m/s
(2) -8/3 kg m/s
(4) 12 kg m/s​

Answer 1

Answer:

the answer is nt listed in the above options its 6

Answer 2

Answer:

The  magnitude of change in momentum of the body=$\sqrt{-4^{2}+4^{2}+2^{2}  }$=$\sqrt{36} = 6\ kg m/s$

Explanation:

Since momentum is the quantity of motion which is performed by the body.

we know that momentum P = mv

where m = mass of the body, v = velocity of the body.

we have m = 1 kg

initial velocity = $v_{i} = \hat{i}-2\hat{j}-3\hat{k}$

final velocity = $v_{f} = -3 \hat{i}+2\hat{j}-\hat{k}$

So, initial momentum=$m\times\ initial\ velocity=1\times\ (\hat{i}-2\hat{j}-3\hat{k})$

                                    = $(\hat{i}-2\hat{j}-3\hat{k})$

Final momentum =$1\times\ -3 \hat{i}+2\hat{j}-\hat{k}$

                            = $(-3 \hat{i}+2\hat{j}-\hat{k})$

So change in momentum =final momentum - initial momentum

                                        =$(-3 \hat{i}+2\hat{j}-\hat{k})\ -\ (\hat{i}-2\hat{j}-3\hat{k})$

                                         =$(-4 \hat{i}+4\hat{j}+2\hat{k})$

The  magnitude of change in momentum of the body=$\sqrt{-4^{2}+4^{2}+2^{2}  }$=$\sqrt{36} = 6\ kg m/s$