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The position vector of a particle vec(R ...

The position vector of a particle `vec(R )` as a funtion of time is given by:
`vec(R )= 4sin(2pit)hat(i)+4cos(2pit)hat(j)`
Where `R` is in meters, `t` is in seconds and `hat(i)` and `hat(j)` denote until vectors along x-and y- directions, respectively Which one of the following statements is wrong for the motion of particle ?

A

Acceleration is along `vec(-R )`

B

Magnitude of accleration vector is `(v^(2))/(R ).`

C

path of the particle is a circle of radius 4 m

D

Magnitude of velocity of particle is 8 m/s

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given position vector of the particle and calculate its velocity and acceleration. Then, we will evaluate the statements provided to determine which one is incorrect. ### Step 1: Write down the position vector The position vector of the particle is given as: \[ \vec{R}(t) = 4 \sin(2\pi t) \hat{i} + 4 \cos(2\pi t) \hat{j} \] ### Step 2: Calculate the velocity vector To find the velocity vector, we differentiate the position vector with respect to time \( t \): \[ \vec{V}(t) = \frac{d\vec{R}}{dt} = \frac{d}{dt}(4 \sin(2\pi t) \hat{i} + 4 \cos(2\pi t) \hat{j}) \] Using the chain rule: \[ \vec{V}(t) = 4 \cdot 2\pi \cos(2\pi t) \hat{i} - 4 \cdot 2\pi \sin(2\pi t) \hat{j} \] \[ \vec{V}(t) = 8\pi \cos(2\pi t) \hat{i} - 8\pi \sin(2\pi t) \hat{j} \] ### Step 3: Calculate the magnitude of the velocity The magnitude of the velocity vector is given by: \[ |\vec{V}| = \sqrt{(8\pi \cos(2\pi t))^2 + (-8\pi \sin(2\pi t))^2} \] \[ |\vec{V}| = \sqrt{64\pi^2 (\cos^2(2\pi t) + \sin^2(2\pi t))} \] Using the Pythagorean identity \(\cos^2(x) + \sin^2(x) = 1\): \[ |\vec{V}| = 8\pi \text{ m/s} \] ### Step 4: Calculate the acceleration vector Next, we differentiate the velocity vector to find the acceleration vector: \[ \vec{A}(t) = \frac{d\vec{V}}{dt} = \frac{d}{dt}(8\pi \cos(2\pi t) \hat{i} - 8\pi \sin(2\pi t) \hat{j}) \] \[ \vec{A}(t) = -8\pi \cdot 2\pi \sin(2\pi t) \hat{i} - 8\pi \cdot 2\pi \cos(2\pi t) \hat{j} \] \[ \vec{A}(t) = -16\pi^2 \sin(2\pi t) \hat{i} - 16\pi^2 \cos(2\pi t) \hat{j} \] ### Step 5: Calculate the magnitude of the acceleration The magnitude of the acceleration vector is: \[ |\vec{A}| = \sqrt{(-16\pi^2 \sin(2\pi t))^2 + (-16\pi^2 \cos(2\pi t))^2} \] \[ |\vec{A}| = 16\pi^2 \sqrt{\sin^2(2\pi t) + \cos^2(2\pi t)} = 16\pi^2 \text{ m/s}^2 \] ### Step 6: Analyze the statements Now, we need to check the statements regarding the motion of the particle: 1. The magnitude of the velocity of the particle is \(8\) m/s. (This is incorrect, as we found it to be \(8\pi\) m/s.) 2. The magnitude of the acceleration is \(16\pi^2\) m/s². (This is correct.) 3. The path of the particle is circular. (This is correct, as shown by the equation \(x^2 + y^2 = 16\).) ### Conclusion The incorrect statement is that the magnitude of the velocity of the particle is \(8\) m/s. The correct value is \(8\pi\) m/s.

To solve the problem, we need to analyze the given position vector of the particle and calculate its velocity and acceleration. Then, we will evaluate the statements provided to determine which one is incorrect. ### Step 1: Write down the position vector The position vector of the particle is given as: \[ \vec{R}(t) = 4 \sin(2\pi t) \hat{i} + 4 \cos(2\pi t) \hat{j} \] ...
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