The speeds of two identical cars are \(u\) and \(4u\) at a specific instant. The ratio of the respective distances in which the two cars are stopped from that instant is:

1. \(1 : 1\)
2. \(1 : 4\)
3. \(1 : 8\)
4. \(1 : 16\)

Subtopic:  Acceleration |
 78%
Level 2: 60%+
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A body is moving with uniform acceleration describes \(40\ \text{m}\) in the first \(5\) seconds and \(65\ \text{m}\) in the next \(5\) seconds. Its initial velocity will be:

1. \(4\ \text{m/s}\)

2. \(2.5\ \text{m/s}\)

3. \(5.5\ \text{m/s}\)

4. \(11\ \text{m/s}\)

Subtopic:  Uniformly Accelerated Motion |
 69%
Level 2: 60%+
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The displacement \(x\) of a particle varies with time \(𝑡\) as \(x=ae^{\alpha t}+be^{\beta t}\) where \(𝑎,\ 𝑏,\ 𝛼\) and \(\beta\) are positive constants. The velocity of the particle will:

1. Go on decreasing with time
2. Be independent of \(𝛼\) and \(\beta\)
3. Drop to zero when \(𝛼 = 𝛽\)
4. Go on increasing with time

Subtopic:  Instantaneous Speed & Instantaneous Velocity |
 55%
Level 3: 35%-60%
PMT - 2005
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A car, starting from rest, accelerates at the rate \(f\) through a distance \(S\), then continues at a constant speed for time \(t\) and then decelerates at the rate \(\frac f2\) to come to rest. If the total distance traversed is \(15\ \text{S}\), then:

1. \(S = \frac{1}{2}ft^2\)
2. \(S = \frac{1}{4}ft^2\)
3. \(S = \frac{1}{72}ft^2\)
4. \(S = \frac{1}{6}ft^2\)

Subtopic:  Acceleration |
 55%
Level 3: 35%-60%
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A man is \(45\ \text{m}\) behind the bus when the bus starts accelerating from rest with an acceleration of \(2.5\ \text{m/s}^2\). With what minimum velocity should the man start running to catch the bus?

1.  \(12\ \text{m/s}\)
2.  \(14\ \text{m/s}\)
3.  \(15\ \text{m/s}\)
4.  \(16\ \text{m/s}\)

Subtopic:  Relative Motion in One Dimension |
 81%
Level 1: 80%+
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A particle moves along the x-axis as \({x}=4({t}-2)+{a}({t}-2)^2.\)Which of the following is true? 

1. The initial velocity of the particle is \(4\)
2. The acceleration of the particle is \(2a\)
3. The particle is at the origin at \( t = 0\)
4. None of these


 

Subtopic:  Instantaneous Speed & Instantaneous Velocity |
 68%
Level 2: 60%+
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A body starting from rest moves with constant acceleration. The ratio of the distance covered by the body during the \(5^{th}\) second to that covered in \(5\) second is:

1. \(9/25\)
2. \(3/5\)
3. \(25/9\)
4. \(1/25\)

Subtopic:  Uniformly Accelerated Motion |
 85%
Level 1: 80%+
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Two trains, each \(50\) m long, are travelling in the opposite direction with velocities \(10\) m/s and \(15\) m/s. The time of crossing is:
1. \(10\) sec
2. \(4\) sec
3. \(2\sqrt{3}\) sec
4. \(4\sqrt{3}\) sec

Subtopic:  Relative Motion in One Dimension |
 80%
Level 1: 80%+
PMT - 1999
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A \(120\ \text{m}\) long train is moving in a direction with speed \(20\ \text{m/s}\). A train \(B\), moving with \(30\ \text{m/s}\) in the opposite direction and \(130\ \text{m}\) long, crosses the first train in a time:

1.  \(4\ \text{s}\)
2.  \(36\ \text{s}\)
3.  \(38\ \text{s}\)
4.  \(5\ \text{s}\)

Subtopic:  Relative Motion in One Dimension |
 87%
Level 1: 80%+
PMT - 1996
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A \(210\) meter long train is moving due north at a speed of \(25\ \text{m/s}\). A small bird is flying due South a little above the train with a speed of \(5\ \text{m/s}\). The time taken by the bird to cross the train is:

1. \(6\ \text{s}\)
2. \(7\ \text{s}\)
3. \(9\ \text{s}\)
4. \(10\ \text{s}\)

Subtopic:  Relative Motion in One Dimension |
 88%
Level 1: 80%+
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