A point P moves counter-clockwise on a circular path of radius 20 m. It sweeps arc length s=t²+5, where s is in metres and t in seconds. Find the magnitude of acceleration at t=5√(3/10) s.

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G1 Physics · Accepted Answer

s=t²+5 gives v=ds/dt=2t and aₜ=2 m/s². At t=5√(3/10), v²=4t²=30, so a꜀=v²/R=30/20=1.5 m/s². Therefore a=√(2²+1.5²)=2.5 m/s², so C.