The position \(x\) of a particle moving along the \(x\)-axis varies with time \(t\) as \(x=20t-5t^2,\)
where \(x\) is in meters and \(t\) is in seconds. The particle reverses its direction of motion at:
1. \(x=40~\text{m}\)
2. \(x=10~\text{m}\)
3. \(x=20~\text{m}\)
4. \(x=30~\text{m}\)
A particle moves a distance \(x\) in time \(t\) according to equation \(x = (t+5)^{-1}\). The acceleration of the particle is proportional to:
1. | \((\text{velocity})^{\frac{3}{2}}\) | 2. | \((\text{distance})^2\) |
3. | \((\text{distance})^{-2}\) | 4. | \((\text{velocity})^{\frac{2}{3}}\) |
Two cars \(A\) and \(B\) are travelling in the same direction with velocities \(v_1\) and \(v_2\) \((v_1>v_2).\) When the car \(A\) is at a distance \(d\) behind car \(B\), the driver of the car \(A\) applied the brake producing uniform retardation \(a\). There will be no collision when:
1. \(d < \frac{\left( v_{1} - v_{2} \right)^{2}}{2 a}\)
2. \(d < \frac{v_{1}^{2} - v_{2}^{2}}{2 a}\)
3. \(d > \frac{\left(v_{1} - v_{2}\right)^{2}}{2 a}\)
4. \(d > \frac{v_{1}^{2} - v_{2}^{2}}{2 a}\)
Which of the following four statements is false?
1. | A body can have zero velocity and still be accelerated. |
2. | A body can have a constant velocity and still have a varying speed. |
3. | A body can have a constant speed and still have a varying velocity. |
4. | The direction of the velocity of a body can change when its acceleration is constant. |
A particle moves along a path \(ABCD\) as shown in the figure. The magnitude of the displacement of the particle from \(A\) to \(D\) is:
1. m
2. \(10\) m
3. m
4. \(15\) m
A body starting from rest moves with uniform acceleration on a horizontal surface. The body covers \(3\) consecutive equal distances from the beginning in time \(t_1, t_2,\text{and}~t_3\) seconds. The ratio of \(t_1:t_2:t_3\) is:
1. \(1:2:3\)
2. \(1:\sqrt{2}:\sqrt{3}\)
3. \(1:\left(\sqrt{2}-1\right):\left(\sqrt{3}-\sqrt{2}\right)\)
4. \(\sqrt{3}:\sqrt{2}:1\)
The position (\(x\)) of a particle in a straight line motion is given by \(x = 2 + 10 t - 5 t^{2}~\text{m}\). Its velocity (\(v\)) is best represented by?
1. | ![]() |
2. | ![]() |
3. | ![]() |
4. | ![]() |
An elevator whose floor to ceiling height is \(12\) meters, moves upward with an acceleration of \(2.2~\text{m/s}^2\). After \(1.5\) seconds since starting, a bolt falls from its ceiling. The time taken by the bolt to reach the floor is:
1. \(1~\text{s}\)
2. \(2~\text{s}\)
3. \(\sqrt{2}~\text{s}\)
4. \(\sqrt{3}~\text{s}\)
The displacement \((x)\) of a point moving in a straight line is given by; \(x=8t^2-4t.\) Then the velocity of the particle is zero at:
1. | \(0.4\) s | 2. | \(0.25\) s |
3. | \(0.5\) s | 4. | \(0.3\) s |
The velocity \(v\) of an object varies with its position \(x\) on a straight line as \(v=3\sqrt{x}.\) Its acceleration versus time \((a\text-t)\) graph is best represented by:
1. | 2. | ||
3. | 4. |