Question

A particle of mass 2 kg is moving along line AB
according to y - x - 4 with speed 4 m/s, then
magnitude of angular momentum about 'O'is​

Answer 1

I think question is ---> A particle of mass 2 kg is moving along 'AB

according to y = x - 4 with speed 4 m/s, then

angular momentum about 'O' is

(1) 16√2 kg m/s

(3) 32 kg m/s

(2) 32√2 kg m/s

(4) 16 kg m/s

solution : see figure, we have to find out perpendicular distance from O to P.

here, we have to find out angular momentum of particle P about origin O.

given, equation of line y = x - 4

or, y = (1)x - 4

hence, slope of line , m = 1 = tanα

so, α = 45° , angle made by line with positive x-axis is 45°.

now see figure, we have to find OP

here, OP = r = 4cos45° = 2√2

then angular momentum = mvr

= 2kg × 4 m/s × 2√2

= 16√2 kg m/s