Motion in a straight line - Live Session - NEET 2020Contact Number: 9667591930 / 8527521718

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Between two stations, a train accelerates from rest uniformly at first, then moves with constant velocity, and finally retards uniformly to come to rest. If the ratio of the time taken is 1 : 8 : 1 and the maximum speed attained be 60 km h^{-1}, then what is the average speed over the whole journey?

1. 48 km h^{-1}

2. 52 km h^{-1}

3. 54 km h^{-1}

4. 56 km h^{-1}

A thief is running away on a straight road in a jeep moving with a speed of 9 m s^{-1}. A policeman chases him on a motor cycle moving at a speed of 10 m s^{-1}. If the instantaneous separation of the jeep from the motor cycle is 100 m, how long will it take for the policeman to catch the thief?

1. 1 s

2. 19 s

3. 90 s

4. 100 s

A body dropped from the top of a tower covers a distance 7x in the last second of its journey, where x is the distance covered in the first second. How much time does it take to reach the ground?

1. 3 s

2. 4 s

3. 5 s

4. 6 s

A train 100 m long traveling at 40 m s^{-1} starts overtaking another train 200 m long traveling at 30 m s^{-1}. The time taken by the first train to pass the second train completely is

1. 30 s

2. 40 s

3. 50 s

4. 60 s

A person is throwing two balls in the air one after the other. He throws the second ball when the first ball is at the highest point. If he is throwing the balls every second, how high do they rise?

1. 5 m

2. 3.75m

3. 2.50 m

4. 1.25 m

The displacement x of a particle moving in one dimension under the action of a constant force is related to time t by the equation $t=\sqrt{x}+3$, where x is in meters and t is in seconds. Find the displacement of the particle when its velocity is zero.

1. zero

2. 12 m

3. 6 m

4. 18 m

A body travels 200 cm in the first 2 s and 220 cm in the next 4 s with constant deceleration. The velocity of the body at the end of the seventh second is

1. 5 cm s^{-1}

2. 10cm s^{-1}

3. 15 cm s^{-1}

4. 20 cm s^{-1}

A body sliding on a smooth inclined plane requires 4 s to reach the bottom, starting from rest at the top. How much time does it take to cover one-fourth the distance starting from rest at the top?

1. 1 s

2. 2 s

3. 4 s

4. 16 s

A ball is dropped into a wekk in which the water level is at a depth h below the top. If the speed of sound is c, then the time after which the splash is heard will be given by

1. $h\left[\sqrt{\frac{2}{gh}}+\frac{1}{c}\right]$

2. $h\left[\sqrt{\frac{2}{gh}}-\frac{1}{c}\right]$

3. $h\left[\frac{2}{g}+\frac{1}{c}\right]$

4. $h\left[\frac{2}{g}-\frac{1}{c}\right]$

A particle slides from rest from the topmost point of a vertical circle of radius r along a smooth chord making an angle $\theta $ with the vertical. The time of descent is

1. Least for $\theta $= 0

2. Maximum for $\theta $= 0

3. Least for $\theta $ =45$\xb0$

4. Independent of $\theta $

For motion of an object along x-axis, the velocity v depends on the displacement x as $v=3{x}^{2}-2x$, then what is the acceleration at x= 2 m.

1. 48 m s^{-2}

2. 80 m s^{-2}

3. 18 m s^{-2}

4. 10 m s^{-2}

A train is moving at a constant speed V when its driver observes another train in front of him on the same track and moving in the same direction with constant speed v. If the distance between the trains is x, then what should be the minimum retardation of the train so as to avoid collision?

1. $\frac{{\left(V+v\right)}^{2}}{x}$

2. $\frac{{\left(V-v\right)}^{2}}{x}$

3. $\frac{{\left(V+v\right)}^{2}}{2x}$

4. $\frac{{\left(V-v\right)}^{2}}{2x}$

The average velocity of a body moving with uniform acceleration after travelling a distance of 3.06 m is 0.34 m s^{-1}. If the change in velocity of the body is 0.18 m s^{-1} during this time, its uniform acceleration is

1. 0.01 m s^{-2}

2. 0.02 m s^{-2}

3. 0.03 m s^{-2}

4. 0.04 m s^{-2}

The velocity-time graph of a particle moving in a straight line is shown in the figure. The acceleration of the particle at t= 9 s is

1. Zero

2. 2.5 m s^{-2}

3. -2.5 m s^{-2}

4. -2 m s^{-2}

The following graph shows the variation of velocity of a rocket with time. Then the maximum height attained by the rocket is

1. 1.1 km

2. 5 km

3. 55 km

4. None of these

An object is thrown up vertically. The velocity-time graph for the motion of the particle is

1.

2.

3.

4.

The displacement versus time curve is given (Figure). Sections OA and BC are parabolic. CD is parallel to the time axis.

Mark the correct match from the following:

1. i$\to $a, ii$\to $c, iii$\to $b, iv$\to $d

2. i$\to $c, ii$\to $d, iii$\to $a, iv$\to $b

3. i$\to $d, ii$\to $b, iii$\to $a, iv$\to $c

4. i$\to $b, ii$\to $a, iii$\to $c, iv$\to $d

**Statement I-** Distance and displacement are different physical quantities.**Statements II-** Distance and displacement have same dimension.

**Statement I-** The displacement of a body may be zero, though its distance can be finite.**Statement II-** If the body moves such that finally it arrives at the initial point, then displacement is zero while distane is finite.

**Statement I-** The average velocity of the body may be equal to its instantaneous velocity.**Statement II-** For a given time interval of a given motion, average velocity is single-valued while average speed can have many values.

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