AC Ep 6th Grade 2012 Final Practice Science Exam (3units)

The unit used to measure force is the newton. Newton is the standard unit of force in the International System of Units (SI). It is named after Sir Isaac Newton and is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. Other options such as cm2, dc, and m3 are not units of force but rather units of area, volume, and length respectively.

The motorcycle in the picture is an example of engineers using a streamlined shape. This means that the design of the motorcycle has been optimized to reduce air resistance and improve aerodynamics. A streamlined shape helps the motorcycle move through the air more efficiently, allowing for higher speeds and better fuel efficiency.

Gravity is the force that makes this man fall. Gravity is the natural force of attraction between two objects with mass, pulling them towards each other. In this case, the force of gravity is pulling the man towards the ground, causing him to fall. Velocity, fear, and air resistance do not directly cause the man to fall, but gravity does.

Adding lubrication to a car engine helps to reduce friction between moving parts. It forms a protective layer between the surfaces, allowing them to glide smoothly against each other. This prevents wear and tear, reduces heat buildup, and improves overall engine performance. Honey, soap, and sugar are not suitable for lubricating car engines as they do not possess the necessary properties to withstand the high temperatures and pressures involved.

A newton meter is a device specifically designed to measure force. It is named after Sir Isaac Newton, who formulated the laws of motion and defined the unit of force known as the newton. A newton meter typically consists of a spring or a calibrated scale that can measure the amount of force applied to it. This device is commonly used in physics experiments and engineering applications to accurately quantify and measure forces.

The person on the bicycle is affected by three kinds of forces: friction with the road, air resistance, and gravity. Gravity is a force that pulls objects towards the center of the Earth. It is responsible for keeping the person and the bicycle grounded, allowing them to maintain balance and stability while riding. Without the force of gravity, the person would not be able to stay on the bicycle and would float away.

When an acid and base react, they undergo a chemical reaction known as neutralization. In this reaction, the acidic and basic properties of the substances are neutralized, resulting in the formation of a salt and water. This process is commonly observed in everyday life, such as when antacids are used to neutralize stomach acid or when baking soda is used to neutralize the acidity of vinegar in cooking. Neutralization reactions are important in various industries, including medicine, agriculture, and wastewater treatment.

The formula F=ma refers to Newton's second law of motion, which states that the force acting on an object is directly proportional to its mass and the acceleration it experiences. This law explains how an object's motion changes when a force is applied to it.

The bicycle in the picture is designed this way to improve speed by reducing air resistance. This design may include features such as a streamlined frame, aerodynamic wheels, and a lower riding position, all of which help to minimize the drag caused by air resistance. By reducing air resistance, the bicycle can move through the air more efficiently, allowing for increased speed.

Water resistance is the correct answer because when an object moves through water, it experiences a force opposing its motion due to the friction between the object and the water molecules. This force is called water resistance. It acts in the opposite direction to the object's motion and slows it down.

When friction force occurs between two objects, energy is released in the form of heat. Friction is the resistance that opposes the relative motion of two surfaces in contact. As the objects rub against each other, the friction generates heat due to the conversion of mechanical energy into thermal energy. This heat energy is a result of the increased kinetic energy of the particles in the objects, causing them to vibrate and collide more intensely. Therefore, heat is the form in which the energy is released during friction.

An airplane is streamlined for traveling through the air quickly so it is aerodynamic. This means that it is designed in a way that reduces air resistance and allows it to move through the air with minimal effort. By having a shape that is sleek and smooth, the airplane can minimize drag and increase its speed and efficiency.

Universal indicator is a chemical solution that changes color depending on the pH level of a substance. When mixed with natural water, which is typically neutral or slightly alkaline, the universal indicator will turn green. This indicates that the pH level of the water is within the range of 7 to 8. Green is the color associated with neutral or slightly alkaline substances, making it the correct answer in this case.

The force of an object can be calculated using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration (F = m*a). In this case, the mass of the motorcycle is given as 200Kg and the acceleration is given as 25 m/s. By substituting these values into the formula, we can calculate the force. Therefore, the force of the motorcycle is 5000N.

This symbol is used to represent a substance that is an irritant. It indicates that exposure to this substance may cause irritation or inflammation to the skin, eyes, or respiratory system. It is important to handle or use such substances with caution to avoid any potential harm or discomfort.

Newton's third law states that for every action, there is an equal and opposite reaction. This means that the reaction to an action will be in the opposite direction and of the same magnitude. Therefore, the correct answer is "opposite."

The mass of an object can be calculated using the formula F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration. Rearranging the formula, we have m = F/a. Plugging in the given values of F = 100 N and a = 12 m/s^2, we get m = 100 N / 12 m/s^2 = 8.33 g. Therefore, the mass of the object is 8.33 g.

The symbol mentioned in the question refers to an unknown symbol or concept, which is not specified in the given information. Therefore, it can be assumed that this symbol could potentially apply to any element, including the alkali metal sodium.

Sir Isaac Newton is indeed famous for discovering the three laws of motion. In addition to these laws, he also formulated the universal law of gravity. This law states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. This discovery revolutionized our understanding of the force of gravity and its effects on objects in motion, and it remains one of Newton's most significant contributions to the field of physics.

Lemon juice is an example of a liquid with a low viscosity because it flows easily and has a thin consistency. Viscosity refers to a liquid's resistance to flow, and liquids with low viscosity flow more easily compared to those with high viscosity. Ketchup, honey, and oil have higher viscosities and are thicker in consistency, making them examples of liquids with higher viscosity.

Friction is a force that opposes the motion of objects when they are in contact with each other. In space, objects may not experience friction in the same way as they do on Earth due to the absence of air or other surfaces to create friction. However, if two objects in space come into contact, they can still experience friction. Therefore, the force of friction can still happen out in space.

The roller blade in the picture reduces friction by decreasing the amount of wheel surface in contact with the road. This is because when there is less surface area in contact with the road, there is less friction generated between the wheels and the road. This allows the roller blade to glide more smoothly and easily.

Citric acid is a weak acid commonly found in citrus fruits. It has a pH of 5, which indicates that it is slightly acidic. The pH scale ranges from 0 to 14, with values below 7 being acidic. Therefore, pH 5 is an appropriate designation for citric acid as it falls within the acidic range of the scale.

A graduated cylinder is a piece of lab equipment used to measure the volume of liquids accurately. It has markings along its side, indicating different volume measurements. This allows scientists to pour a liquid into the cylinder and read the exact volume it occupies. The other options mentioned, such as a beaker, conical flask, and test tube, are also common lab equipment but do not have the same precise volume measurements as a graduated cylinder.

Dish soap is not an alkali because it is typically a mixture of surfactants and detergents, which are not classified as alkalis. Sodium hydroxide, on the other hand, is an alkali because it is a strong base that dissociates in water to produce hydroxide ions. Therefore, the correct answer is dish soap and sodium hydroxide.