Q. No.The position-time \((x-t)\) graphs for two children \(A\) and \(B\) returning from their school O to their homes P and Q respectively are shown in the graph. Choose the incorrect statement.
1.
\(B\) reaches home faster than \(A.\)
2.
\(B\) overtakes \(A\) on the road twice.
3.
\(B\) walks faster than \(A.\)
4.
\(A\) lives closer to the school than \(B.\)
A car moving along a straight highway with a speed of \(126\) km/h is brought to a stop within a distance of \(200\) m. How long does it take for the car to stop?
1. \(10.2\) s
2. \(9.6\) s
3. \(11.4\) s
4. \(6.7\) s
The figure gives the \((\mathrm{x-t})\) plot of a particle in a one-dimensional motion. Three different equal intervals of time are shown. The signs of average velocity for each of the intervals \(1,\) \(2\) & \(3,\) respectively are:
| 1. | \(-,-,+\) |
| 2. | \(+,-,+\) |
| 3. | \(-,+,+\) |
| 4. | \(+,+,-\) |
The figure gives a speed-time graph of a particle in motion along the same direction. Three equal intervals of time are shown. In which interval is the average acceleration greatest in magnitude?
| 1. | Interval 2
|
2. | Interval 1
|
| 3. | Interval 3
|
4. | Equal in all intervals |
A boy standing on a stationary lift (open from above) throws a ball upwards with the maximum initial speed he can, equal to How much time does the ball take to return to his hands?
1. 5 s
2. 10 s
3. 15 s
4. 7 s
A passenger arriving in a new town wishes to go from the station to a hotel located 10 km away on a straight road from the station. A dishonest cabman takes him along a circuitous path 23 km long and reaches the hotel in 28 min. The average speed of the taxi is:
1. 30 km/h
2. 49.3 km/h
3. 55.6 km/h
4. 60 km/h
A car moves with a speed of \(60\) km/h for \(1\) hour in the east direction and with the same speed for \(30\) min in the south direction. The displacement of the car from the initial position is:
1. \(60\) km
2. \(30 \sqrt{2}\) km
3. \(30 \sqrt{5}\) km
4. \(60 \sqrt{2}\) km
A body in one-dimensional motion has zero speed at an instant. At that instant, it must have:
| 1. | zero velocity. | 2. | zero acceleration. |
| 3. | non-zero velocity. | 4. | non-zero acceleration. |
If a particle is moving along a straight line with increasing speed, then:
| 1. | its acceleration is negative. |
| 2. | its acceleration may be decreasing. |
| 3. | its acceleration is positive. |
| 4. | both (2) & (3) |
When the velocity of a body is variable, then:
1. its speed may be constant.
2. its acceleration may be constant.
3. its average acceleration may be constant.
4. All of the above
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