Chap 9 Forces & Energy

2 types of forces

1. Contact forces

   Frictional force

   2. Non-contact forces

      Gravitational force

      Magnetic force

      Electrostatic force

Work Done in Science: Work is done when a force causes an object to move in the direction of the force. The formula for work (W) is:

• W = F × d × cos(θ)

  • W is work (measured in joules),

  • F is the magnitude of the force applied (in newtons),

  • d is the distance moved by the object in the direction of the force (in meters)

• Key Points:

  • Work is done only if the object moves; if there is no displacement, despite the force applied, no work is done.

  • Work can be positive (force and displacement in the same direction), negative (force and displacement in opposite directions), or zero (force is perpendicular to the direction of displacement or no movement occurs).

  • Work is an important concept in physics, particularly in mechanics, and is related to energy transfer.