AimMent

For Class 8, 9 & 10

Foundation - a strong base in Physics, Chemistry, Maths & Biology

Concept-first questions with clear model answers across all four subjects, aligned to NCERT. Start early, build the habit, and walk into your board exams, NEET and JEE already ahead.

Class 824Class 924Class 1036
SubjectAllPhysics 19Chemistry 19Biology 19Mathematics 27
ChapterAllAtoms and MoleculesForce and Laws of MotionGravitationHeron's FormulaImprovement in Food ResourcesIs Matter Around Us PureLinear Equations in Two VariablesMatter in Our SurroundingsMotionNatural ResourcesNumber SystemsPolynomialsSoundStatisticsStructure of the AtomSurface Areas and VolumesThe Fundamental Unit of LifeTissuesWork and Energy

Showing 1 question for Class 9. Tap a card to reveal the answer.

PhysicsWork and Energymedium

Define work done by a force and state the formula for kinetic energy.

Reveal answer ↓

What it is

Work is force times the distance moved along it; a moving object stores that work as kinetic energy.

Answer

Work is done when a force acts on a body and the body moves in the direction of the force; work done W = F s cos(theta), where s is the displacement and theta is the angle between the force and the displacement. Kinetic energy is the energy possessed by a body due to its motion and is given by KE = (1/2) m v^2. The unit of both work and energy is the joule.

W = F s cos(theta) ; KE = (1/2) m v^2

  • •Work needs force and displacement along it
  • •W = F s cos(theta)
  • •Kinetic energy KE = (1/2) m v^2
  • •Unit is the joule (J)

Why learn this

It underlies electricity bills (energy) and how a dam, a bow-and-arrow or a moving car works.

💡 Memory trick

No movement, no work. KE = 1/2 m v^2 - double the speed, FOUR times the energy.