3.2 Work

• Work in physics is the transfer of energy when a force causes displacement. energy
• In the work formula, θ represents the angle between force and displacement
• Negative work decreases an object's kinetic energy.


  True
• Work is negative when the force opposes motion
• Positive work increases an object's kinetic energy.

  True
• Positive work increases kinetic energy, while negative work decreases it.
• What is an example of negative work?

  Friction slowing down a car
• What type of work is done when a force assists motion and increases kinetic energy?

  Positive work
• What is work measured in?

  Joules
• Match the angle with the corresponding cosine value and work done:

  0° ↔️ 1, Maximum positive work

  90° ↔️ 0, No work done

  180° ↔️ -1, Maximum negative work
• When the angle between force and displacement is 90°, no work is done.


  True
• What effect does positive work have on kinetic energy?

  Increases it
• Negative work reduces the kinetic energy of an object.
• What is an example of positive work being done?

  Lifting a heavy object
• A 50 N force pulls a box 10 meters at 30°. What is the work done approximately?

  433 joules
• What effect does positive work have on the energy of a system?

  Increases it
• The formula for work is W = F \times d \times \cos(\theta)</latex>


  True
• What type of work is done when the force aids the motion of an object?

  Positive work
• Match the type of work with its description and example:

  Positive Work ↔️ Force supports motion, increasing kinetic energy; Pushing a box across the floor

  Negative Work ↔️ Force opposes motion, decreasing kinetic energy; Friction slowing down a moving car
• What does θ represent in the work formula?

  Angle between force and displacement
• What is the work done when the angle between force and displacement is 90 degrees?

  No work done
• Pushing a box across the floor is an example of positive work.


  True
• Order the following angles and their corresponding work done from highest positive to highest negative:

  1️⃣ 0°: Maximum positive work

  2️⃣ 90°: No work done

  3️⃣ 180°: Maximum negative work
• Negative work occurs when a force opposes motion, decreasing kinetic energy.


  True
• The angle in the work equation represents the direction between the force and displacement.


  True
• What is the value of cos(0°)?

  1
• Maximum negative work is done when the angle between force and displacement is 180°
• Give an example of negative work being done.

  Friction slowing down a car
• Steps to solve work problems

  1️⃣ Identify variables: force, displacement, and angle

  2️⃣ Use the formula: W = F \times d \times \cos(\theta)</latex>

  3️⃣ Plug in values

  4️⃣ Calculate the work done
• Work is the process of transferring energy from one object or system to another.


  True