A test car starts out from rest on a horizontal circular track of 80m radius and increases it's speed at a uniform rate to reach 27.78 m/s in 10s. Find the magnitude of the total acceleration of the car 8s after the start.

Ok so I know that the total acceleration is the square root of the tangential acceleration squared plus the normal acceleration squared. What I'm not sure of is how to find these components at t = 8s, since the velocity isn't constant then. It says that it increases it's speed at a constant rate to reach the 27.78 m/s so does that mean that the acceleration is the same for any time during that 10s interval? Any help would be appreciated

2 answers

The radial accleration is V^2/R, where V is the velocity at that time. At t=8 s, V would be 4/5 of 27.78 m/s.

The tangential acceleration is the tate at which the speed increases with time, which is 2.778 m/s^2
thank you so much! this really helped me see where i went wrong