Answer:
a) T = 2 π√ (m / k) c) T = 2 s , f = 0.5 Hz
Step-by-step explanation:
 a) In an oscillatory system the angular velocity is 
 w = √ (k / m)
 
where w is the angular velocity, k the constant of the spring and m the applied mass 
the angular velocity is related to the frequency and the period 
 w = 2π f 
 f = 1 / T 
 w = 2π / T 
 
 we substitute 
 2π / T = √ k / m 
 T = 2 π√ (m / k) 
b) The units If kilograms (m = [kg]) are for the masses, the spring constant is in Newton per meters (k = [N / m], angular velocity in (w = [rad / s] 
c) they ask us the period if we have 10 cycles in 5 s 
 T = 10/5 
 T = 2 s 
 f = 1 / T 
 f = 0.5 Hz