NTA Abhyas JEE Main2020PhysicsMotion in Two DimensionsPractice
A particle moves in space along the path z = a x 3 + b y 2 in such a way that d x d t = c = d y d t where a , b and c are constants. The acceleration of the particle is
Options
- A6 a c 2 x + 2 b c 2 k ^
- B2 a x 2 + 6 b y 2 k ^
- C4 b c 2 x + 3 a c 2 k ^
- Db c 2 x + 2 b y k ^
Correct answer
A. 6 a c 2 x + 2 b c 2 k ^
Step-by-step solution
Given that d x d t = d y d t = c ∴ d 2 x d t 2 = d 2 y d t 2 = 0 Further z = ax 3 + by 2 ∴ d z d t = 3 a x 2 d x d t + 2 b y d y d t = 3 a c x 2 + 2 b c y d x d t = c = d y d t ∴ d 2 z d t 2 = 6 a c x d x d t + 2 b c d y d t = 6ac 2 x + 2bc 2 Now acceleration of particle is a → = d 2 x d t 2 i ^ + d 2 y d t 2 j ^ + d 2 z d t 2 k ^ = 6 a c 2 x + 2 b c 2 k ^