A particle of mass 2 kg is moving such that at time t , its position, in meter, is given by r ( t ) = 5 i ^ − 2 t 2 j ^ . The angular momentum of the particle at t = 2 s about the origin in kg m − 2

Question

A particle of mass 2 kg is moving such that at time t , its position, in meter, is given by r ( t ) = 5 i ^ − 2 t 2 j ^ ​ . The angular momentum of the particle at t = 2 s about the origin in kg m − 2 s − 1 is :

TestHub · Accepted Answer

Angular momentum L = m ( v × r ) ​ = 2 kg ( dt dr ​ × r ) = 2 kg ( 4 t × × 5 i − 2 t 2 j ^ ​ ) = 2 kg ( − 20 t k ^ ) = 2 kg × − 20 × 2 m − 2 s − 1 k ^ = − 80 k ^ ​

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