The kilogram is the Standard International System of Units unit of mass. It is defined as the mass of a particular international prototype made of platinum-iridium and kept at the International Bureau of Weights and Measures.
Answer:
B. +m
Explanation:
The magnification of an image is defined as the ratio between the size of the image and of the object:

where we have
y' = size of the image
y = size of the object
There are two possible situations:
- When m is positive, y' has same sign as y: this means that the image image is upright
- When m is negative, y' has opposite sign to y: this means that the image is upside down
Therefore, the correct option representing an upright image is
B. +m
Answer:
The equation of the time-dependent function of the position is 
(b) is correct option.
Explanation:
Given that,
Length = 12 cm
Mass = 200 g
Extend distance = 27 cm
Distance = 5 cm
Phase angle =0°
We need to calculate the spring constant
Using formula of restoring force





We need to calculate the time period
Using formula of time period

Put the value into the formula


At t = 0, the maximum displacement was 5 cm
So, The equation of the time-dependent function of the position

Put the value into the formula




Hence, The equation of the time-dependent function of the position is 
Velocity = distance /time
acceleration = velocity / time
Atoms are always neutral it means, the number of Protons & electrons are equal in them whereas ions are charged, the number is different depends on the kind of charge
Hope this helps!