Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Force: A push or pull acting on an object. It can change the shape, size, speed, or direction of an object. Force is measured in Newtons ().
Work: In science, work is said to be done when a force applied to an object causes it to move a certain distance in the direction of the force. If the object does not move, work done is .
Energy: The ability or capacity to do work. Common forms include Solar energy, Wind energy, and Heat energy.
Simple Machines: Tools that make our work easier and faster by changing the direction or amount of force required. There are six main types: Lever, Pulley, Wheel and Axle, Inclined Plane, Screw, and Wedge.
Lever: A stiff rod that turns around a fixed point called the Fulcrum. Examples include scissors and see-saws.
Inclined Plane: A sloping surface used to move heavy loads to a higher level with less effort, such as a ramp or a slide.
Pulley: A simple machine consisting of a wheel with a groove for a rope, used to lift heavy objects like a bucket from a well.
Wedge: A tool with at least one slanting side ending in a sharp edge, used to cut or split objects (e.g., an axe or a knife).
📐Formulae
💡Examples
Problem 1:
Rohan pushes a heavy table with a force of , but the table does not move at all. How much work has Rohan done?
Solution:
Explanation:
Since the distance () moved by the table is , the work done is calculated as . Work is only done when there is displacement.
Problem 2:
A laborer uses a force of to push a cart over a distance of . Calculate the work done.
Solution:
Explanation:
Using the formula , we get .
Problem 3:
Identify the simple machine used in a bottle opener.
Solution:
Lever
Explanation:
A bottle opener acts as a lever where the handle provides the effort, the cap is the load, and the edge of the cap acts as the fulcrum.