Question

a body is moving in a straight line along x-axis its distance from the origin is given by the equation x=at^2 bt^3 ,where x is in metre and T is in second find average speed of the body in the interval t is equal to zero and t is equal to 2 and its instantaneous speed at t is equal to 2 second.​

Answer 1

Solution-: A body is moving in a straight line along x-axis its distance from the origin is given by the equation x=at^2 bt^3.

Equation is x= t^2 - 4t + 6


x= t^2 - 4t +6

As we know that,

v= dx/dt

Therefore,

v = d (t^2 - 4t + 6)/dt = (2t - 4)

On substituting value of t as 0 and 3 sec we get

u= -4 m/s

v= 2 m/s

Now,

Average Speed= u+v/2
=>-4+2/2
= -2/2
= -1 m/s

Average Speed= -1 m/s.

So, speed is not in negative.

[So, Average Speed= 1 m/s. ]