Answer:
Chemical change
Explanation:
A chemical change is what happens. The food digested changes smell due to some enzyme the has acted on the food which catalyzes the rate of digestion. The enzymes acts on the food in order to speed up the rate of the reaction (digestion) and in turn causing the smell.
"Unbalanced forces" show themselves as a change in the speed
or direction of an object's motion.
The only choice where the speed or direction of motion is changing
is the car that's slowing down for the light.
Explanation:
It is given that,
Spring constant of the spring, k = 15 N/m
Amplitude of the oscillation, A = 7.5 cm = 0.075 m
Number of oscillations, N = 31
Time, t = 15 s
(a) Let m is the mass of the ball. The frequency of oscillation of the spring is given by :

Total number of oscillation per unit time is called frequency of oscillation. Here, 


m = 0.0895 kg
or
m = 89 g
(b) The maximum speed of the ball that is given by :





Hence, this is the required solution.