A car moves with a constant velocity of 10 m/s for 10 sec along a straight track then it moves with uniform acceleration of 2m/s^2 for 5sec. Find the total displacement and velocity at the end of 5 th sec of acceleration.
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Answers
Answer:
The first part of the motion of the car in discussion is a uniform type of motion where there is no variation in the acceleration with time .
Therefore for the specified time interval i.e. for 10 seconds the car moves with a constant velocity of 10 m/s and is displaced by 10 m/s x 10s = 100 m (Assuming the car is moving in a straight line .)
Therefore displacement at the end of 10 s = 100m
The second part of the problem deals with the body being accelerated .
Therefore as a consequence of this uniform acceleration ( the acceleration does not vary with time i.e =2m/s2) , the velocity will increase linearly with time given by the equation v= u + at
the parameters are as follows : u= initial velocity=10m/s
a= acceleration= 2m/s2
t= time interval under consideration
thus the final velocity at the end of the 5 seconds of accelerated motion is
10 m/s + (2m/s2)(5s)= 20 m/s
Therefore the displacement at the end of the 5 seconds is given by
s= ut +1/2 at2
which when the values are substituted should give you an answer of 75 m
BUT……….
we have totally forgotten about the displacement in the initial 10 seconds of the motion .
Therefore the total displacement at the end of 15 seconds is 100m +75m= 175m
Hope this helps….
Explanation: