Final exam

Speed is the $ext{distance}$ travelled by an object per unit time.
An object in $ext{uniform}$ motion moves at a constant speed in a fixed direction.
A car that is braking is an example of $ext{non-uniform}$ motion.
A $ext{free-body}$ diagram is used to show all the forces acting on an object.
Laboratory instrument used to measure the size of a force is called a spring $ext{balance}$ .
The standard international unit of force is $ext{newton}$ .
Magnetic force and force of gravity are examples of $ext{non-contact}$ forces.
Forces that allow an object to stay at rest or in uniform motion are $ext{balanced}$ forces.
The amount of matter an object contains, which is constant in different places is called $ext{mass}$ .
The force of gravity of the Earth acting on an object is its $ext{weight}$ .
An object of mass 1 kg has a weight of only 1.6 N on the $ext{moon}$ .
$ext{Friction}$ is a contact force that opposes the motion of objects between two surfaces.
Opposing force that increases when an object moves faster in air is $ext{air}$ resistance.
To reduce friction, we can separate surfaces by adding $ext{lubricants}$ or an air cushion.
High-speed trains use a $ext{streamlined}$ shape to minimize fluid resistance.
Action and reaction forces are always equal in $ext{magnitude}$ but opposite in direction.
Vinegar contains $ext{ethanoic}$ acid, while citrus fruits contain citric acid.
Acids taste sour, while alkalis have a $ext{bitter}$ taste and a slippery feel.
Acids can change the color of blue litmus paper to $ext{red}$ .
The measurement scale for the acidity or alkalinity of a substance is called the $ext{pH}$ scale.
A reusable instrument that measures the pH value more accurately than pH paper is a pH $ext{meter}$ .
Neutralization is a chemical reaction between an acid and an alkali to form $ext{salt}$ and water.
In the stomach, excess acid can be treated by taking a tablet called an $ext{antacid}$ .
Farmers often add an alkali like calcium hydroxide to regulate the pH value of $ext{soil}$ .