In a two-dimensional motion, the instantaneous speed of a particle remains constant at a positive value \(v_0.\) Which of the following statements must always be true?

1. The particle has zero acceleration.
2. The particle’s acceleration is increasing.
3. The particle’s acceleration always lies in the plane of motion.
4. The particle necessarily moves in a uniform circular path.
Subtopic:  Acceleration |
Level 3: 35%-60%
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The position vector of a particle \(\overrightarrow r\) as a function of time \(t\) (in seconds) is \(\overrightarrow r=3 t \hat{i}+2t^2\hat j~\text{m}\). The initial acceleration of the particle is:
1. \(2~\text{m/s}^2\)
2. \(3~\text{m/s}^2\)
3. \(4~\text{m/s}^2\)

4. zero

Subtopic:  Acceleration |
 88%
Level 1: 80%+
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The \(x\) and \(y\) coordinates of the particle at any time are \(x=5 t-2 t^2\) and \({y}=10{t}\) respectively, where \(x\) and \(y\) are in meters and \(\mathrm{t}\) in seconds. The acceleration of the particle at \(\mathrm{t}=2\) s is:

1. \(5\hat{i}~\text{m/s}^2\) 2. \(-4\hat{i}~\text{m/s}^2\)
3. \(-8\hat{j}~\text{m/s}^2\) 4. \(0\)
Subtopic:  Acceleration |
 84%
Level 1: 80%+
NEET - 2017
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A body is moving with a velocity of \(30~\text{m/s}\) towards the east. After \(10~\text s,\) its velocity becomes \(40~\text{m/s}\) towards the north. The average acceleration of the body is:
1. \( 7~\text{m/s}^2\)
2. \( \sqrt{7}~\text{m/s}^2\)
3. \(5~\text{m/s}^2\)
4. \(1~\text{m/s}^2\)

Subtopic:  Acceleration |
 78%
Level 2: 60%+
AIPMT - 2011
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If the position of a particle varies according to the equations \(x= 3t^2\), \(y =2t\), and \(z= 4t+4\), then which of the following is incorrect?

1. Velocities in \(y\) and \(z\) directions are constant
2. Acceleration in the \(x\text-\)direction is non-uniform
3. Acceleration in the \(x\text-\)direction is uniform
4. Motion is not in a straight line
Subtopic:  Acceleration |
 77%
Level 2: 60%+
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A particle is moving in the \(XY\) plane such that \(x = \left(t^2 -2t\right)~\text m,\) and \(y = \left(2t^2-t\right)~\text m,\) then:

1. the acceleration is zero at \(t=1~\text s.\) 
2. the speed is zero at \(t=0~\text s.\)
3. the acceleration is always zero.
4. the speed is \(3~\text{m/s}\) at \(t=1~\text s.\)
Subtopic:  Acceleration |
 73%
Level 2: 60%+
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A particle moves so that its position vector is given by \(r=\cos \omega t \hat{x}+\sin \omega t \hat{y}\) where \(\omega\) is a constant. Based on the information given, which of the following is true?

1. The velocity and acceleration, both are parallel to \(r.\)
2. The velocity is perpendicular to \(r\) and acceleration is directed towards the origin.
3. The velocity is not perpendicular to \(r\) and acceleration is directed away from the origin.
4. The velocity and acceleration, both are perpendicular to \(r.\)
Subtopic:  Acceleration |
 71%
Level 2: 60%+
NEET - 2016
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A particle moves in space such that:
\(x=2t^3+3t+4;~y=t^2+4t-1;~z=2\sin\pi t\)
where \(x,~y,~z\)  are measured in meters and \(t\) in seconds. The acceleration of the particle at \(t=3\) seconds will be:

1. \(36 \hat{i}+2 \hat{j}+\hat{k} \) ms-2
2. \(36 \hat{i}+2 \hat{j}+\pi \hat{k} \) ms-2
3. \(36 \hat{i}+2 \hat{j} \) ms-2
4. \(12 \hat{i}+2 \hat{j} \) ms-2
Subtopic:  Acceleration |
 69%
Level 2: 60%+
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A particle moving on a curved path possesses a velocity of \(3\) m/s towards the north at an instant. After \(10\) s, it is moving with speed \(4\) m/s towards the west. The average acceleration of the particle is:

1. \(0.25~\text{m/s}^2,\) \(37^{\circ}\) south to east.
2. \(0.25~\text{m/s}^2,\) \(37^{\circ}\) west to north.
3. \(0.5~\text{m/s}^2,\) \(37^{\circ}\) east to north.
4. \(0.5~\text{m/s}^2,\) \(37^{\circ}\) south to west.

Subtopic:  Acceleration |
 71%
Level 2: 60%+
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A particle is moving along a curve. Select the correct statement.

1. If its speed is constant, then it has no acceleration.
2. If its speed is increasing, then the acceleration of the particle is along its direction of motion.
3. If its speed is decreasing, then the acceleration of the particle is opposite to its direction of motion.
4. If its speed is constant, its acceleration is perpendicular to its velocity.
Subtopic:  Acceleration |
 71%
Level 2: 60%+
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