1.
Forces can _______________ an object.
Correct Answer
A. Stop the motion of
Explanation
Forces can stop the motion of an object by counteracting the force that is causing it to move. When an object is in motion, it possesses kinetic energy. By applying a force in the opposite direction, the force can cancel out the object's motion and bring it to a stop. This can be observed in everyday situations, such as when a person pushes a shopping cart and then applies a force in the opposite direction to bring it to a stop.
2.
Which of the following is NOT a type of force?
Correct Answer
C. Heat
Explanation
Heat is not considered a type of force because it is a form of energy transfer, specifically the transfer of thermal energy between objects. While forces can cause changes in temperature, heat itself is not a force. Forces, such as gravitational and magnetic forces, act upon objects to cause them to move or change direction. Weight, on the other hand, is a force that is the result of gravity acting on an object's mass.
3.
What is the SI unit of force?
Correct Answer
D. Newton
Explanation
The SI unit of force is the Newton. This unit is named after Sir Isaac Newton, who made significant contributions to the field of physics. The Newton is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. It is widely used in various scientific and engineering fields to measure and quantify forces.
4.
Which of the following action involves a push and a pull?
Correct Answer
D. Turning a steering wheel
Explanation
Turning a steering wheel involves both a push and a pull action. When turning the wheel to the left, one hand pushes the wheel in that direction while the other hand pulls it towards oneself. This combination of pushing and pulling is necessary to successfully turn the steering wheel and control the direction of the vehicle.
5.
It would probably be easiest to ride a bicycle across
Correct Answer
D. Concrete road
Explanation
Riding a bicycle on a concrete road would be the easiest option compared to riding on gravel, sand, or grass. Concrete roads provide a smooth and stable surface, which allows for better traction and control of the bicycle. Gravel, sand, and grass can be uneven and unstable, making it more difficult to ride a bicycle and potentially causing accidents or loss of balance. Therefore, choosing a concrete road would be the most convenient and safest option for riding a bicycle.
6.
The force that always acts opposite to the direction of the motion of an object is called
Correct Answer
C. Friction
Explanation
Friction is the force that always acts opposite to the direction of the motion of an object. It occurs when two surfaces come into contact and resist each other's motion. Friction is responsible for slowing down or stopping the motion of objects and is present in various everyday situations, such as when walking on a surface or when a car's brakes are applied. In this case, the force of friction opposes the forward motion of the object, making it the correct answer.
7.
Which is NOT a force?
Correct Answer
A. Mass
Explanation
Mass is not a force but a measure of the amount of matter in an object. It is a scalar quantity that remains constant regardless of the location of the object. Force, on the other hand, is a vector quantity that can cause an object to accelerate or change its motion. Weight is the force exerted by gravity on an object, gravity is the force of attraction between objects, and air resistance is the force that opposes the motion of an object through the air.
8.
The following helps to reduce the friction when moving a cabinet EXCEPT
Correct Answer
A. Moving on a rough surface
Explanation
Moving on a rough surface increases friction, making it harder to move the cabinet. The other options all help to reduce friction: putting lubricant on the surface reduces the friction between the cabinet and the surface, removing the content in the cabinet reduces the weight and therefore the friction, and placing wheels for the cabinet reduces the contact area and friction.
9.
The amount of force exerted on an object due to gravity is the
Correct Answer
B. Weight
Explanation
Weight is the correct answer because weight is the force exerted on an object due to gravity. It is the measure of the gravitational force acting on an object's mass. The weight of an object can vary depending on the strength of the gravitational field it is in, but the mass of the object remains constant. Therefore, weight is the appropriate term to describe the force exerted on an object due to gravity.
10.
Which of the following is a contact force?
Correct Answer
B. Air resistance
Explanation
Air resistance is a contact force because it occurs when an object moves through the air and experiences resistance due to the collision of air molecules with its surface. This force is directly proportional to the speed and surface area of the object, and it opposes the motion of the object. Unlike static electricity, magnetic force, and gravity, which are non-contact forces, air resistance requires direct contact between the object and the air molecules to occur.
11.
The amount of matter in an object is the
Correct Answer
C. Mass
Explanation
Mass refers to the amount of matter in an object. It is a measure of the inertia of an object and is independent of its location or the gravitational force acting on it. Weight, on the other hand, is the force exerted on an object due to gravity and varies with the strength of the gravitational field. Gravity is the force of attraction between two objects, and load refers to the weight or burden carried by an object. Therefore, the correct answer is mass as it specifically addresses the amount of matter in an object.
12.
The tendency of an object to remain at rest if at rest or to continue moving in a straight line if in motion is called
Correct Answer
B. Inertia
Explanation
Inertia is the tendency of an object to resist changes in its state of motion. If an object is at rest, it tends to stay at rest, and if it is in motion, it tends to continue moving in a straight line at a constant speed. Inertia is a property of matter and is related to mass. The greater the mass of an object, the greater its inertia. Friction, force, and acceleration are all related concepts but do not specifically describe the tendency of an object to remain at rest or continue moving in a straight line.
13.
Your weight changes on different planets. Which is the most important factor?
Correct Answer
B. The size of the planet
Explanation
The most important factor that determines the change in weight on different planets is the size of the planet. Weight is directly proportional to the mass of an object, and the mass of a planet is determined by its size. Therefore, the larger the planet, the greater the gravitational force it exerts, resulting in a higher weight for objects on its surface. The distance away from the Sun, the density of the planet, and the magnetic effect of the planet do not directly affect an individual's weight.
14.
Which of the following metals is NOT magnetic?
Correct Answer
C. Aluminium
Explanation
Aluminium is not magnetic because it is a non-ferrous metal, meaning it does not contain iron. While iron, cobalt, and nickel are all ferromagnetic metals, aluminium does not possess the necessary properties to be attracted to a magnet.
15.
What is a magnetic field?
Correct Answer
C. The space around a magnet where the force of a magnet can act.
Explanation
The correct answer is "The space around a magnet where the force of a magnet can act." A magnetic field is the region or space surrounding a magnet where its influence or force can be felt. It is characterized by the ability to exert magnetic forces on other magnets or magnetic materials within its vicinity. The strength and direction of the magnetic field can vary depending on the properties of the magnet.
16.
In a bar magnet, the strongest magnetic force is
Correct Answer
D. At both poles
Explanation
In a bar magnet, the strongest magnetic force is at both poles. This is because the poles of a magnet are the regions where the magnetic field lines are most concentrated. At the North pole, the magnetic field lines emerge from the magnet, while at the South pole, they converge into the magnet. The concentration of these field lines results in a stronger magnetic force at both poles compared to the middle of the magnet.
17.
You can magnetise a nail by
Correct Answer
A. Stroking the nail with a magnet in one direction for 30 times
Explanation
Stroking the nail with a magnet in one direction for 30 times aligns the domains of the nail's atoms in the same direction, creating a magnetic field. This process, known as magnetic induction, causes the nail to become magnetized and acquire magnetic properties. Heating the nail, moving it to and fro on a bar magnet, or using sandpaper to polish it do not have the same effect of aligning the domains and therefore do not magnetize the nail.
18.
Which of the following is CORRECT?
Correct Answer
B. South pole attracts north pole
Explanation
The correct answer is that the south pole attracts the north pole. This is because opposite poles attract each other according to the laws of magnetism. The north pole of a magnet has a magnetic field that flows towards the south pole, creating a force of attraction between the two poles.
19.
What is the term used to represent the micro-magnets in a magnetic substance?
Correct Answer
B. Domains
Explanation
The term used to represent the micro-magnets in a magnetic substance is "domains". Domains are small regions within a magnetic material where the magnetic moments of the atoms align in the same direction, creating a localized magnetic field. These domains can be thought of as tiny magnets within the larger material.
20.
The following set up is used to build
Correct Answer
C. An electromagnet nail
Explanation
An electromagnet nail is the correct answer because it is the only option that fits the given setup. The setup requires a nail that can be heated and also has magnetic properties. The other options either do not have the ability to be heated or do not have magnetic properties. Therefore, the electromagnet nail is the most suitable choice for the given setup.
21.
Photosynthesis is a process in which green plants use ________ to make their own ________.
Correct Answer
sunlight
food
Explanation
Photosynthesis is the process by which green plants convert sunlight into food through a series of chemical reactions. The plants use the energy from sunlight to convert carbon dioxide and water into glucose (a type of sugar) and release oxygen as a byproduct. This glucose serves as the plant's food source, providing energy for growth and development. Therefore, the correct answer is sunlight and food.
22.
A bar magnet is suspended freely from a string. Describe the behavior of the magnet when it comes to rest, and explain the underlying magnetic forces causing this behavior.