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.	\(+,+,-\)

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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?

A boy standing on a stationary lift (open from above) throws a ball upwards with the maximum initial speed he can, equal to $49$ $m$ $s^{-1}.$  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 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:

If a particle is moving along a straight line with increasing speed, then:

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

A particle moves with velocity v₁ for time t₁ and v₂ for time t₂ along a straight line. The magnitude of its average acceleration is:

1. $\frac{v_2-v_1}{t_1-t_2}$

2. $\frac{v_2-v_1}{t_1+t_2}$

3. $\frac{v_2-v_1}{t_2-t_1}$

4. $\frac{v_1+v_2}{t_1-t_2}$

A body is projected vertically in the upward direction from the surface of the earth. If the upward direction is taken as positive, then the acceleration of the body during its upward and downward journey is:

1. Positive, negative

2. Negative, negative

3. Positive, positive

4. Negative, positive

A car travelling at a speed of 30 km/h is brought to rest at a distance of 8 m by applying brakes. If the same car is moving at a speed of 60 km/h, then it can be brought to rest with the same brakes in:

1. 64 m

2. 32 m

3. 16 m

4. 4 m