Hello!

Find the acceleration using the formula a = (vf - vi) / t where:
vf = final velocity
vi = initial velocity
t = time
Plug in the points above:
vf = +10 m/s
vi = +20 m/s
t = 5 sec
(10 - 20) / 5 = -10 / 5 = -2 m/s²
Yeah I guess it makes sense
Explanation:
Given that,
Mass of the hamster, m = 0.139 kg
Diameter of the wheel, d = 20.8 cm
Radius, r = 10.4 m
Frequency of the wheel, f = 1 Hz
Time, t = 0.823 s
(a) There exist a relationship between the tangential and angular acceleration of the wheel. It is given by :

Since, 




(b) In radial direction, applying the second law of motion as :

a is the radial acceleration, 








Hence, this is the required solution.