Home
Class 12
PHYSICS
A unit mass has vecr=8hati-4hatj and v...

A unit mass has `vecr=8hati-4hatj and vecv=8hati+4hatj` What is its angular momentum ?

A

`64 hatk` unit

B

`64hatj` unit

C

`64hati` unit

D

`32hatk` unit

Text Solution

Verified by Experts

The correct Answer is:
A
Tha angular momentum , `L=vecrxxvecp=vecrxxmvecv`
`therefore " "vecL=m(vecrxxvecv)" but m"=1, therefore vecL=vecr xxvecv`
`therefore L=(8hati-4hatj)xx(8hati+4hatj)`
`therefore |L|=|(hati,hatj,hatk),(8,-4,0),(8,4,0)|`
`=hati(0-0)-hatj(0-0)+hatk[8xx4-(-8xx4)]` ,brgt `therefore|L|=64hatk" unit"`
Promotional Banner

Topper's Solved these Questions

  • ROTATIONAL MOTION

    MARVEL PUBLICATION|Exercise TEST YOUR GRASP - 3|8 Videos

  • OSCILLATIONS

    MARVEL PUBLICATION|Exercise MCQ|368 Videos

  • SEMICONDUCTORS

    MARVEL PUBLICATION|Exercise MCQs|261 Videos

Similar Questions

Explore conceptually related problems

Given r=4hatj and p=2hati+3hatj+hatk . The angular momentum is

The position of a particle is given by vecr=(hati+2hatj-hatk) and momentum vecp=(3hati+4hatj-2hatk) . The angular momentum is perpendicular to the

A unit mass at position vector vecr=(3hati+hatj) is moving with velocity vecv=(5hati-6hatj) . What is the angular momentum of the body about the origin?

If for some particle its position vector and linear momentum are respectively be 2hati+hatj+hatk and 2hati-3hatj+hatk . Its angular momentum will be:

The position vector vecr and linear momentum vecp and vecr=hati and vecp=4hatj the angular momentum vector is perpendicular to

Let vecu= hati+hatj, vecv = hati -hatj and vecw = hati+2hatj+3hatk . If hatn is a unit vector such that vecu.hatn =0 and vecv.hatn=0 then find the value of |vecw.hatn|

If vecp = hati + hatj, vecq = 4hatk - hatj " and " vecr =hati + hatk , then the unit vector in the direction of 3vecp+ vecq - 2vecr is

The velociies of A and B are vecv_(A)= 2hati + 4hatj and vecv_(B) = 3hati - 7hatj , velocity of B as observed by A is