28 is balanced and unbalanced
Answer:
k = 5.05 N/m
Explanation:
In order to calculate the spring mass of the system, you use the following formula:
(1)
T: period of oscillation of the system
m: mass of the air-track glider = 200g = 0.200 kg
k: spring constant = ?
You first calculate the period of oscillation:

Next, you solve the equation (1) for k, and then you replace the values of the other parmateres:

The spring constant of the spring is 5.05 N/m
It will reflect because polished metal is like glass or water it’s shiny and smooth
The first: alright, first: you draw the person in the elevator, then draw a red arrow, pointing downwards, beginning from his center of mass. This arrow is representing the gravitational force, Fg.
You can always calculate this right away, if you know his mass, by multiplying his weight in kg by the gravitational constant

let's do it for this case:

the unit of your fg will be in Newton [N]
so, first step solved, Fg is 637.65N
Fg is a field force by the way, and at the same time, the elevator is pushing up on him with 637.65N, so you draw another arrow pointing upwards, ending at the tip of the downwards arrow.
now let's calculate the force of the elevator

so you draw another arrow which is pointing downwards on him, because the elevator is accelating him upwards, making him heavier
the elevator force in this case is a contact force, because it only comes to existence while the two are touching, while Fg is the same everywhere