Physics-
General
Easy
Question
A point starts moving in a straight line with a certain acceleration. At a time 
after beginning of motion the acceleration suddenly becomes retardation of the same value. The time in which the point returns to the initial point is
- Cannot be predicted unless acceleration is given
The correct answer is:
In this problem point starts moving with uniform acceleration 
and after time (Position 
) the direction of acceleration get reversed i.e. the retardation of same value works on the point. Due to this velocity of points goes on decreasing and at position 
its velocity becomes zero. Now the direction of motion of point reversed and it moves from 
to 
under the effect of acceleration .
We have to calculate the total time in this motion.
Starting velocity at position is equal to zero.
Velocity at position 
[
]
Distance between and 
As same amount of retardation works on a point and it comes to rest therefore
and time required to cover this distance is also equal to 
Now for the return journey from 
Hence total time in which point returns to initial point
Related Questions to study
Physics-
Which of the following statements is correct?
Which of the following statements is correct?
Physics-General
Physics-
A body 
starts from rest with an acceleration 
After 2 seconds, another body 
starts from rest with an acceleration 
If they travel equal distances in the 5th second, after the start of A, then the ration 
is equal to
A body starts from rest with an acceleration After 2 seconds, another body starts from rest with an acceleration If they travel equal distances in the 5th second, after the start of A, then the ration is equal to
Physics-General
Physics-
A particle of mass 
is initially situated at the point 
inside a hemispherical surface of radius 
as shown in figure. A horizontal acceleration of magnitude
is suddenly produced on the particle in the horizontal direction. If gravitational acceleration is neglected, the time taken by particle to touch the sphere again is
A particle of mass is initially situated at the point inside a hemispherical surface of radius as shown in figure. A horizontal acceleration of magnitudeis suddenly produced on the particle in the horizontal direction. If gravitational acceleration is neglected, the time taken by particle to touch the sphere again isPhysics-General
Physics-General
Physics-
A ball is thrown vertically upwards with a velocity of 
from the top of a tower of height 
. How long will it travel before it hits ground
A ball is thrown vertically upwards with a velocity of from the top of a tower of height . How long will it travel before it hits ground
Physics-General
Physics-
A car starts from rest and moves with uniform acceleration on a straight road from time 
to 
. After that, a constant deceleration brings it to rest. In this process the average speed of the car is
A car starts from rest and moves with uniform acceleration on a straight road from time to . After that, a constant deceleration brings it to rest. In this process the average speed of the car is
Physics-General
Physics-
A packet is dropped from a balloon which is going upwards with the velocity 
, the velocity of the packet after 2 seconds will be
A packet is dropped from a balloon which is going upwards with the velocity , the velocity of the packet after 2 seconds will be
Physics-General
Physics-
An elevator car, whose floor to ceiling distance is equal to 2.7
starts ascending with constant acceleration of 
2 
after the start, a bolt begins falling from the ceiling of the car. The free fall time of the bolt is
An elevator car, whose floor to ceiling distance is equal to 2.7 starts ascending with constant acceleration of 2 after the start, a bolt begins falling from the ceiling of the car. The free fall time of the bolt is
Physics-General
Physics-
A cyclist starts from the centre
of a circular park of radius 1 km, reaches the edge of the park, then cycles along the circumference and returns to the point as shown in figure. If the round trip takes 10 min, the net displacement and average speed of the cyclist (in metre and kilometer per hour) are
A cyclist starts from the centre of a circular park of radius 1 km, reaches the edge of the park, then cycles along the circumference and returns to the point as shown in figure. If the round trip takes 10 min, the net displacement and average speed of the cyclist (in metre and kilometer per hour) arePhysics-General
Physics-General
Physics-
At he instant a motor bike starts from rest in a given direction, a car overtakes the motor bike, both moving in the same direction. The speed-time graphs for motor bike and car are represented by 
and 
respectively.
Then
At he instant a motor bike starts from rest in a given direction, a car overtakes the motor bike, both moving in the same direction. The speed-time graphs for motor bike and car are represented by and respectively.
Then
Physics-General
Physics-General
Physics-
Look at the graphs [a] to [d] carefully and indicate which of these possibly represents one dimensional motion of a particle
Look at the graphs [a] to [d] carefully and indicate which of these possibly represents one dimensional motion of a particle
Physics-General
Physics-
A particle is projected up with an initial velocity of 
. The ball will be at a height of 
from the ground after
A particle is projected up with an initial velocity of . The ball will be at a height of from the ground after
Physics-General
Physics-
A particle is projected upwards. The times corresponding to height 
while ascending and while descending are 
and 
respectively. The velocity of projection will be
A particle is projected upwards. The times corresponding to height while ascending and while descending are and respectively. The velocity of projection will be
Physics-General
Physics-
Acceleration of a particle changes when
Acceleration of a particle changes when
Physics-General
Physics-
A particle shows distance-time curve as given in this figure. The maximum instantaneous velocity of the particle is around the point
A particle shows distance-time curve as given in this figure. The maximum instantaneous velocity of the particle is around the pointPhysics-General
Physics-General
Physics-
The displacement- time graph for two particles and are straight lines inclined at angles of 
and 
with the time axis. The ratio of velocities of 
is
The displacement- time graph for two particles and are straight lines inclined at angles of and with the time axis. The ratio of velocities of is
Physics-General
