Year 10 Physics: Contact And Non-Contact Forces Explained

🧲 Detailed Explanation of Contact and Non-Contact Forces

📌 What Are Contact Forces?

Contact forces happen when two objects physically touch each other. The force is transferred through direct contact. For example:

• Friction: This force occurs when two surfaces slide against each other, like your shoes rubbing on the ground.
• Tension: The force in a rope or string when it pulls on an object, such as when you pull a wagon with a rope.
• Normal Force: The force supporting an object resting on a surface, like the table pushing up on a book.
• Applied Force: A force applied by a person or object directly onto another, such as pushing a door open.

Contact forces can either pull or push, and they always require physical contact between objects.

🌌 What Are Non-Contact Forces?

Non-contact forces, on the other hand, act over a distance. This means objects don’t need to touch for these forces to act. Some examples are:

• Gravitational Force: The force that pulls objects towards the Earth, keeping us grounded.
• Magnetic Force: The force between magnets or between a magnet and magnetic materials.
• Electrostatic Force: The force between charged objects, which can either attract or repel without contact.

These forces can influence objects even when they are separated by space.

🔍 Key Differences Between Contact and Non-Contact Forces

💡 Why Understanding These Forces Is Important

Knowing the difference helps explain how objects move and interact. For example, why does an apple fall from a tree? The answer is gravitational force – a non-contact force. But why does a book stop sliding? Because friction, a contact force, slows it down.

📚 Study Tips for Learning About Forces

• Draw diagrams of forces acting on objects to visualize contact and non-contact forces.
• Use everyday examples to spot different forces in action.
• Practice labeling forces in physics questions to become confident in distinguishing them.

By understanding contact and non-contact forces, you’ll be better prepared to explore more complex physics concepts like motion, energy, and Newton’s laws. Keep practising by identifying these forces around you! ✨

❓ 10 Examination-Style 1-Mark Questions on Contact and Non-Contact Forces

1. What type of force is friction?
   Answer: Contact
2. Which force pulls objects towards Earth?
   Answer: Gravity
3. What is the force called when two magnets push or pull each other without touching?
   Answer: Magnetic
4. Which force acts between charged objects without contact?
   Answer: Electrostatic
5. What force opposes the motion of a sliding object?
   Answer: Friction
6. What force causes an apple to fall from a tree?
   Answer: Gravity
7. What force acts when you push a door open?
   Answer: Contact
8. Which force keeps the Moon orbiting the Earth?
   Answer: Gravity
9. What force exists between two objects that are touching?
   Answer: Contact
10. What type of force can act at a distance without physical contact?
    Answer: Non-contact

📝 10 Examination-Style 2-Mark Questions on Contact and Non-Contact Forces

1. What is the difference between contact and non-contact forces?
   Contact forces require objects to touch, while non-contact forces act at a distance without physical contact.
2. Give one example of a contact force.
   Friction is an example of a contact force.
3. Give one example of a non-contact force.
   Gravity is an example of a non-contact force.
4. Explain why magnetic forces are considered non-contact forces.
   Magnetic forces act on objects without needing to physically touch them.
5. What type of force causes an object to slow down when it is sliding on a surface?
   Friction is the contact force that slows down a sliding object.
6. Name the force that pulls objects towards the Earth.
   The gravitational force pulls objects towards the Earth.
7. Which force keeps planets orbiting around the sun without touching it?
   The gravitational force keeps planets orbiting around the sun.
8. How does air resistance affect a falling object?
   Air resistance is a contact force that opposes the motion of a falling object.
9. Why do two magnets either attract or repel each other without touching?
   Because magnetic forces act at a distance as non-contact forces.
10. State one effect of a contact force acting on an object.
    A contact force can change the motion or shape of an object.

✍️ 10 Examination-Style 4-Mark Questions on Contact and Non-Contact Forces

Question 1

Explain the difference between contact and non-contact forces. Give one example of each and describe how they act on objects.

Answer:
Contact forces occur when two objects physically touch each other. An example is friction, which acts between two surfaces in contact and opposes motion. Non-contact forces act over a distance without touching. Gravity is a non-contact force, pulling objects toward the Earth. In contact forces, interaction requires physical contact, while non-contact forces work through fields such as gravitational or magnetic fields. Both types of forces can cause changes in motion.

Question 2

Describe how friction affects the motion of a moving object and explain why it is considered a contact force.

Answer:
Friction acts between two surfaces in contact, opposing the relative motion between them. It slows down or stops moving objects by converting kinetic energy into heat. Friction is a contact force because it only occurs when surfaces are physically touching. For example, when a car’s tyres grip the road, friction prevents it from slipping. The rougher the surfaces, the greater the friction. Without friction, it would be difficult to walk or drive safely.

Question 3

A magnet pulls a paperclip across a table without touching it. Identify the force and explain how it works as a non-contact force.

Answer:
The force is a magnetic force, which is a type of non-contact force. It acts through the magnetic field generated by the magnet, attracting the paperclip without the two objects touching. This force can attract or repel objects made of certain materials like iron or steel. The magnetic force decreases with distance but doesn’t require physical contact. Because the magnet acts at a distance, it is classified as a non-contact force. This force can move the paperclip across the table without the magnet touching it.

Question 4

Explain why weight is considered a non-contact force and describe how it depends on gravitational force.

Answer:
Weight is the force of gravity acting on an object’s mass. It pulls objects toward the Earth without any physical contact, making it a non-contact force. The gravitational force depends on both the mass of the object and the mass of the Earth. Weight is calculated using the formula weight = mass × gravitational field strength (W = mg). This force acts vertically downwards towards the centre of the Earth. Since gravity can act over a distance, weight is always present even if the object is not touching anything.

Question 5

Describe the role of air resistance as a contact force when an object is falling through the atmosphere.

Answer:
Air resistance is a type of friction force that acts opposite to the direction of a falling object’s motion. It occurs because air particles collide with the surface of the object, slowing it down. Since the object physically contacts air molecules, air resistance is a contact force. Its magnitude increases with the object’s speed and surface area. Air resistance can balance the weight force, causing the object to reach terminal velocity. This force reduces acceleration during free fall.

Question 6

A book rests on a table without moving. Identify and explain the forces acting on the book, including contact and non-contact forces.

Answer:
The book experiences its weight, a non-contact force due to gravity pulling it downwards. The table provides an equal and opposite contact force called the normal reaction force, pushing upwards. These two forces balance, so the book remains at rest. The forces act on the book but in opposite directions, resulting in zero net force. No motion occurs because the forces are equal in size and opposite in direction. The contact force from the table stops the book from falling.

Question 7

Explain how the electrostatic force works as a non-contact force and give an example involving everyday objects.

Answer:
Electrostatic force occurs between electrically charged objects without them touching each other, so it is a non-contact force. Oppositely charged objects attract, while like charges repel each other. An everyday example is when a balloon rubbed on hair sticks to a wall. The rubbing causes a transfer of electrons, charging the balloon and wall with opposite charges. The electrostatic force pulls the balloon towards the wall through the electric field. This force acts at a distance, demonstrating how charges interact without contact.

Question 8

Compare and contrast magnetic force and gravitational force as non-contact forces.

Answer:
Both magnetic and gravitational forces are non-contact forces acting at a distance. Gravitational force attracts objects with mass towards each other and is always attractive. Magnetic force can either attract or repel depending on the poles involved. Gravity acts on all objects with mass, whereas magnetic force only affects magnetic materials and charged particles. Magnetic forces vary depending on the orientation of poles; gravitational force is always directed towards the centre of mass. Both forces decrease in strength with increased distance.

Question 9

A toy car moves across a flat surface and comes to a stop. Explain the forces that caused it to decelerate and stop, focusing on contact forces.

Answer:
The toy car slows down and stops mainly because of friction, a contact force between the car’s wheels and the surface. Friction opposes the motion, converting kinetic energy into heat. Air resistance also acts against the car’s movement, another contact force with air molecules. Together, these forces cause the car to decelerate. Without these forces, the car would keep moving at constant speed due to inertia. Once these forces balance or exceed the driving force, the car eventually stops.

Question 10

Illustrate how tension in a rope is an example of a contact force and describe a scenario where this force is present.

Answer:
Tension is the force transmitted through a rope or string when it is pulled tight by forces acting at both ends. It is a contact force because it occurs through physical contact within the rope’s fibres. For example, when a person pulls a sled with a rope, tension acts along the rope to pull the sled forward. This force helps transfer force from the person to the sled to move it. If the rope is slack, there is no tension force. Tension always pulls along the rope’s length, opposing the pulling force.

💪 10 Examination-Style 6-Mark Questions on Contact and Non-Contact Forces for Year 10

Question 1

Explain the difference between contact forces and non-contact forces. Provide two examples of each type of force and describe how they act on objects.

Question 2

Describe how the force of friction acts as a contact force when a box is pushed across the floor. Include in your answer why friction is important in everyday life.

Question 3

A magnet attracts a paperclip without touching it. Explain what type of force is acting here and how non-contact forces can influence objects at a distance.

Question 4

Explain how gravitational force is a non-contact force. Describe how this force affects an apple falling from a tree and its role in keeping the Earth and the Moon in orbit.

Question 5

Describe the forces involved when a person pushes a swing. Identify which forces are contact forces and which are non-contact forces, and explain their effects on the swing’s motion.

Question 6

Explain how the force of air resistance acts on a skydiver during a jump. Discuss why air resistance is considered a contact force and how it affects the skydiver’s speed.

Question 7

An iron ball is held above a magnet and then released. Describe the forces acting on the ball from the moment it is released until it hits the magnet, and explain how these forces change the ball’s motion.

Question 8

Explain how electrostatic forces are examples of non-contact forces. Provide an example of electrostatic forces in everyday life and describe what causes these forces.

Question 9

Describe the forces acting on a book resting on a table. Explain the role of contact forces in keeping the book stationary and what would happen if these forces changed.

Question 10

Explain how the tension in a rope acts as a contact force when a person pulls a boat to the shore. Include in your answer how the forces on the rope affect both the person and the boat.

Each answer should include clear explanations of the forces involved, examples where applicable, and the effects of these forces on objects’ motion or position. Use key terms like contact force, non-contact force, friction, gravity, magnetic force, electrostatic force, air resistance, tension, and normal contact force to demonstrate understanding.