The acceleration \(a\) (in ) of a body, starting from rest varies with time \(t\) (in \(\mathrm{s}\)) as per the equation \(a=3t+4.\) The velocity of the body at time \(t=2\) \(\mathrm{s}\) will be:
1. \(10\)
2. \(18\)
3. \(14\)
4. \(26\)
A point moves in a straight line under the retardation a. If the initial velocity is \(\mathrm{u},\) the distance covered in \(\mathrm{t}\) seconds is:
1.
2.
3.
4.
The relation between time and distance is given by , where α and β are constants. The retardation, as calculated based on this equation, will be (assume v to be velocity) :
1.
2.
3.
4.
The displacement of a particle is given by . The initial velocity and acceleration are, respectively:
1. | \(\mathrm{b}, ~\mathrm{-4d}\) | 2. | \(\mathrm{-b},~ \mathrm{2c}\) |
3. | \(\mathrm{b}, ~\mathrm{2c}\) | 4. | \(\mathrm{2c}, ~\mathrm{-2d}\) |
An elevator car, whose floor to ceiling distance is equal to 2.7 m, starts ascending with constant acceleration of 1.2 ms–2. 2 sec after the start, a bolt begins falling from the ceiling of the car. The free fall time of the bolt is
1.
2.
3. 0.7 s
4. 1 s
The acceleration ‘a’ in m/s2 of a particle is given by where t is the time. If the particle starts out with a velocity, u = 2 m/s at t = 0, then the velocity at the end of 2 seconds will be:
1. 12 m/s
2. 18 m/s
3. 27 m/s
4. 36 m/s
A particle moves along a straight line such that its displacement at any time t is given by metres. The velocity when the acceleration is zero is:
1. | 4 ms-1 | 2. | −12 ms−1 |
3. | 42 ms−1 | 4. | −9 ms−1 |
The position \(x\) of a particle varies with time \(t\) as \(x=at^2-bt^3\). The acceleration of the particle will be zero at time \(t\) equal to:
1. | \(\dfrac{a}{b}\) | 2. | \(\dfrac{2a}{3b}\) |
3. | \(\dfrac{a}{3b}\) | 4. | zero |
The relation \(3t = \sqrt{3x} + 6\) describes the displacement of a particle in one direction where \(x\) is in metres and \(t\) in seconds. The displacement, when velocity is zero, is:
1. | \(24\) metres | 2. | \(12\) metres |
3. | \(5\) metres | 4. | zero |
A student is standing at a distance of 50 metres from the bus. As soon as the bus begins its motion with an acceleration of 1 ms–2, the student starts running towards the bus with a uniform velocity u. Assuming the motion to be along a straight road, the minimum value of u, so that the student is able to catch the bus is:
1. 5 ms–1
2. 8 ms–1
3. 10 ms–1
4. 12 ms–1