Forces Flashcards

Forces

Definition

• A force is a push, pull, stretching, or twisting action on an object.

• Forces can change an object's shape, speed, or direction.

Types of Forces

• Examples include:

  • Pull

  • Push

  • Friction

  • Air resistance

  • Gravitational force

  • Buoyancy

  • Thrust

  • Magnetic force

  • Weight

  • Reaction force

Forces Work in Pairs

• Forces always occur in pairs.

• These pairs involve interactions between objects (e.g., gravity acting on both the girls and the Earth).

Measurement of Forces

• Forces are measured in Newtons (N).

Mass vs. Weight

• Mass:

  • Definition: Amount of matter in an object.

  • Units: Kilograms (kg), grams (g)

• Weight:

  • Definition: The gravitational force between an object and the Earth.

  • Units: Newtons (N)

• The relationship between mass and weight:

  • As mass increases, weight increases.

Key Concepts

• Forces are often represented using arrows in diagrams.

• Forces can be contact or non-contact forces.

• Forces explain changes in object movement and can be measured with a newtonmeter.

• Forces always come in pairs and are measured in Newtons.

Investigating Friction

Definition

• Friction is a force that slows down an object.

Key Concepts

• Rough surfaces cause more friction than smoother surfaces.

Experiment Variables

• Independent Variable: Type of surface.

• Dependent Variable: Time taken for the object to reach the bottom of the ramp.

• Control Variable: Same object, the angle of elevation of the ramp.

Results

• Data is recorded to keep results in order.

• Average (Mean) is calculated by adding the values and dividing by the number of values.

Conclusion

• The rougher the surface, the higher the friction.

Investigating Air Resistance

Definition

• Air resistance is a force that slows down an object in the air.

Key Concepts

• Larger surface area causes more air resistance than smaller surface area.

• Air resistance is a resistive force.

Experiment Variables

• Independent Variable: Size of parachute (Surface area).

• Dependent Variable: Time taken for the object to drop.

• Control Variable: The mass of the object, the material, the height dropped.

Conclusion

• The larger the surface area, the higher the air resistance.

Gravity

Definition

• Gravity is a force of attraction between objects with mass.

Key Concepts

• The larger the mass of an object, the higher the gravitational pull.

• Objects are attracted towards the center of the Earth.

Factors Affecting Gravity

• Mass: The greater the mass, the greater the gravity.
  Gravity and Air Resistance

• In the absence of air resistance (e.g., on the Moon), objects fall at the same rate regardless of their surface area.

Weight Calculation

• Weight is calculated using the formula: $Weight = Mass \times Gravity$ or $w = m \times g$

• Mass is calculated using the formula: $Mass = Weight / Gravity$ or $m= w / g$