Question

A motor cyclist moving with velocity of 72 km/h

Answer 1

is moving with the speed of a 5 / 18 * 72 metre per second

Answer 2

Seems like your question is incomplete.

Question:- A motor-cyclist moving with a velocity of 72 km/hr on a flat road takes a turn on the road at a point where the radius of curvature of the road is 20 meter. The acceleration due to gravity is 10 m/s². In order to avoid sliding, he must not bend with respect to the vertical plane by an angle greater.

Answer:

             While taking a turn with a uniform speed b motorcyclist lean towards an angle θ with the vertical such that

                   tan θ = v²/rg

where,      

             v = 20m/s , r = 20 m , g = 10m/s

∴        tan θ = (20)²/20 × 10

                    = 2

=>   θ = tan⁻¹2

Good luck !