A runner begins a race from the starting line and accelerates to a speed of 9.8 m/s. If it takes the runner 12.8 seconds to reach his maximum speed, what was his acceleration?

an energy transformation flow diagram is shown

where is it ?

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft