b) 4m/s/s
This is because you divide the speed you reach, by the time it takes to get to that speed:
12m/s ÷ 3s = 4m/s/s
The units come from what you divide, meters per second ÷ seconds this can be written as m/s/s or ms-²
Answer:
A. Two tennis balls that are near each other
Explanation:
The formula for gravitational force (F) between two objects is

where m₁ and m₂ are the masses of the two objects, d is the distance between their centres, and G is the gravitational constant.
Thus, two objects that are far from each other will have a smaller gravitational force. We can eliminate Options C and D.
If the objects are at the same distance, those with the smaller mass will have a smaller force.
The mass of a tennis ball is 57 g.
The mass of a soccer ball is 430 g.
Two tennis balls that are near each other will have a smaller gravitational attraction.
The ozone layer that is inside the stratosphere blocks UV radiation.
The ozone layer contains high concentrations of ozone relative to other parts of the atmosphere. This was discovered by Charles Fabry and Henri Buisson who are both French Physicists.
The ozone in the earth's stratosphere is created through ultraviolet light striking a group of ordinary oxygen molecules containing two oxygen atoms, subsequently splitting them into individual oxygen atoms and finally these said atomic oxygen then combines with unbroken O2 to create ozone (O3).
An element would be the type of substance that only contains one kind of matter.