JEE MAIN - PHYSICS

Question

The position (x) of a body moving along a straight line at time t is given by, x=(t²-3t) m, find distance travelled by the body in the time interval 1s to 3s. 

Answer 1

I am not clear as to what this question is asking.  

Do you want to know where the body is at time 1s, and where the body is at time 3s, and therefore what distance is the body at 3s from where it was at 1s?  In that case, the body after 3s is 2m away from where is was at 1s.

A much harder question is how far did the body travel from time 1s until time 3s?  In other words the body traveling along the path given by x = t²-3t. This is finding the length of the arc described by that equation.  This is a much harder problem.  I cannot write out all of the work but I can tell you the the distance traveled in that time interval will be approximately 3.4002 m.

Comments

Please provide detailed step.
Thankyou

Answer 2

x(0)=0

x(1)=1^{2 -} 3(1)=-2

x(2)=2²-3(2)=-2

x(3)=3²-3(3)=0

so the object stayed at 2 meter for 1s and 2s and moved to 0m so the magnitude of distance travelled is 2m