Tangential acceleration is asked... It is = the derivative of the tangential velocity.

* acceleration = dv / dt = d (a t ) / dt = a*

*this is always constant.*

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Completion of 1/8 of revolution means: Ф = angle turned = π/4 radians, or the distance traveled is = 2πR / 8 = π R/4

t = time

v = instantaneous linear speed along the circular arc = a * t

radius = R

ω = instantaneous angular velocity = v / r = a t / R

linear displacement s = integral v * dt

So s = a t² / 2, we choose s = 0 at t = 0

= π R / 4

=> t² = (πR) / (2a)

t = √ [ πR / (2a) ]

This is the time taken to reach the point where the body covered 1/8 of the revolution.

tangential or Linear acceleration = dv/dt = a, it is always a constant.

centripetal acceleration = v² / R = a² t² / R

resultant acceleration will be the net result of the two components.