Question

A body of mass 1 Kg is moving with velocity vi= i cap -2j cap -3k cap m/s^2 and after 10s velocity of body becomes vf= -3i cap+2j cap-kcap m/s^2 .The magnitude of change in momentum of the body is
1. 4kg m/s
2. -8√3kg m/s
3. 4√3 kgm/s
4. 12 kg m /s
(ans. :3.)
Can someone solve??

Answer 1

Answer:

6 kgm/s

Explanation:

A body of mass 1 Kg is moving with velocity vi= i cap -2j cap -3k cap m/s²

Vi =  i - 2j  - 3 k

Initial Momentum = mVi  =  i - 2j  - 3 k  kgm/s

after 10s velocity of body becomes vf= -3i cap+2j cap-kcap m/s²

Vf= -3i +2j -k

Final Momentum = MVf = -3i +2j -k kgm/s

Change in Momentum = Final Momentum - Initial Momentum

=  -3i +2j -k  - ( i - 2j  - 3 k)

= - 4i + 4j + 2k

Magnitude = √4² + 4² + 2²  = √36  = 6 kgm/s

None of the given options:

if one of k sign changes then

Magnitude = √4² + 4² + 4²  = √48 = 4√3  kgm/s  , option 3

Answer 2

Answer:

option 3 is the correct answer for this question