10 Questions
What term is used in science to describe a push or pull on an object?
Force
Which characteristic of force expresses its strength?
Magnitude
What type of force is exerted when kicking a football?
Push
What do vector quantities in science express?
Magnitude and direction
Which force is responsible for the attraction or repulsion between two magnetic bodies?
Magnetic force
What is the definition of inertia based on the text?
Tendency of an object to resist changes in its velocity
Which type of force requires touch or contact to be applied?
Muscular force
What is the upward force exerted by a fluid on an object known as?
Upthrust
What is the significance of velocity in defining the state of motion of an object?
Velocity shows the direction of the object's motion
What type of forces are Gravitational force and Electrostatic force classified as?
Non-contact forces
Study Notes
Introduction to Force
- A push or pull of an object is known as force, which arises from the interaction between two objects.
- Force has both magnitude and direction, and its strength is expressed in magnitude.
- Force brings about a change in the direction or state of motion of a body.
Types of Force
- A push is a force exerted away from the body, e.g., hitting a snooker ball or kicking a football.
- A pull is a force exerted towards the body, e.g., drawing a bucket of water from a well or playing tug of war.
- Magnetic force is the force of attraction or repulsion between two magnetic bodies due to their poles.
Characteristics of Force
- Force is a vector quantity, expressed in magnitude and direction.
- Vectors are used to find the resultant component acting on a body when multiple forces act on it.
- Net force is the resulting force acting on an object when multiple forces are applied.
Application of Force
- A force can change the state of an object at rest or in motion.
- It can change an object's direction and velocity.
- Force can also change the shape of an object.
State of Motion
- The state of motion of an object is defined by its velocity, which is the speed with a direction.
- Inertia is the tendency of an object to resist changes in its velocity.
- An object at rest or in motion will remain in its state of motion unless an unbalanced force is applied.
Contact Forces
- Contact forces require a touch or contact to be applied, e.g., muscular forces and frictional forces.
- Muscular force is the force applied by the effort of our muscles, e.g., lifting a heavy box or pulling a bucket of water.
Non-Contact Forces
- Non-contact forces do not require a touch or contact to be applied, e.g., gravitational force, electrostatic force, and nuclear forces.
- Electrostatic force is the force of attraction or repulsion experienced by a charged body from another charged body.
Pressure
- Pressure is the force exerted per unit area, and its distribution is affected by the shape of the object.
- Pressure in fluids is transmitted undiminished in all directions on the walls of the container.
- Upthrust or buoyant force is the upward force exerted by a fluid on an object.
- Atmospheric pressure is the pressure exerted by gases in the air on the surface of the Earth.
Explore key concepts related to force and pressure as per the CBSE Class 8 syllabus. Understand the characteristics, types, and effects of force on objects. Test your knowledge on forces and pressures in this chapter.
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