  Difficult Questions

## Motion In A Straight Line

- Are you well prepared? Practice hard questions to be more confident about the chapter
1
The position of a particle travelling along x axis is given by  where is in and is in second. Then
This question has multiple correct options
A
the body comes to rest firstly at and then at
B
the total displacement of the particle in travelling from the first zero of velocity to the second zero of velocity is zero
C
the total displacement of the particle in travelling from the first zero of velocity to the second zero of velocity is .
D
the particle reverses its velocity at s and then at s and has a negative velocity for < t <
2
From point located on a highway (shown in figure above) one has to get by car as soon as possible to point located in the field at a distance  from the highway. It is known that the car moves in the field  times slower than on the highway. At a distance from point  one must turn off the highway. Find .
3
A driver takes to apply the brakes after he sees a need for it. This is called the reaction time of the driver. If he is driving a car at a speed of and the brakes causes a deceleration of , find the distance traveled by the car after he sees the need to put the brakes on.
A
B
C
D
4
Two particles A and B move with velocities  respectively along the x and y axis.  The initial separation between them is 'd' as shown in the figure. Find the least distance between them during their motion
A
B
C
D
5
Two particles instantaneously at and are , apart and they are moving with uniform velocities, the former towards at and the latter perpendicular to at . They are nearest at the instant (in seconds)
A
B
C
D
6
A particle is thrown vertically upward with a speed of 100 m/s . What is distance of particle travelled in 15 sec ?
7
A train stops at two stations P and Q which are 2 km apart, It accelerates uniformly from for 15 seconds and maintains a constant speed for a time before decelerating uniformly to rest at Q. If the deceleration is , find the time for which the train is travelling at a constant speed.
A
B
C
D
8
Starting from rest a particle moves in a straight line with acceleration

The velocity of particle at t = 7s is:
A
11 m/s
B
22 m/s
C
33 m/s
D
44 m/s
9
A street car moves rectilinearly from station (here car stops) to next station (here also car stops) with an acceleration varying according to the law , where and are positive constants and is the distance from station . If the maximum distance between the two stations is then find .
10
A hunter is at units. He observes two preys at units and respectively. At zero instant he starts moving in the plane of their positions with uniform speed of in a direction perpendicular to line till he sees and collinear at time . Time is
A
B
C
D