Forces and Work

• What is a force?


  A force is a pushing or pulling action on an object.
• How can we apply a pushing force?


  We can apply a pushing force to a box with our hand.
• What is an example of a lifting force?


  Our arms can supply a lifting force to some weights.
• What is a drag force?


  A drag force is created by a parachute between us and the air when skydiving.
• What can forces do to the motion of an object?


  Forces can make objects move, stop them, speed them up, slow them down, or change their shape.
• How does a pushing force affect a box?


  The pushing force makes the box move and slide along the floor.
• What happens when a lifting force is applied to weights?


  The lifting force makes the weights rise up off the ground.
• Why is a parachute used when skydiving?


  A parachute creates a drag force that slows the person down for a safer landing.
• What is work in the context of forces?

  Work is a transfer of energy caused by a force that moves an object through a distance.
• How does work relate to the box example?


  Our hand applies a force to the box, making it move forward some distance.
• What energy changes occur when our hand pushes the box?

  The chemical energy from our hand is transferred to kinetic energy in the box.
• What does the force do in the context of energy transfer?


  The force transfers chemical energy from our hand to kinetic energy in the box.
• What is the main concept to understand about work?

  Work is an energy transfer that happens when a force moves an object through a distance.
• What happens when an object moves in the direction of a force?


  The force does work to give the object kinetic energy.
• How does a slingshot work in terms of energy transfer?


  A slingshot provides an elastic force that transfers elastic potential energy to a rock.
• What happens to a stationary rock when an elastic force is applied?


  The stationary rock goes from having zero kinetic energy to some kinetic energy, making it start moving.
• What happens when a space shuttle's engines provide a drive force?


  The engines transfer chemical energy from the fuel to the shuttle, increasing its kinetic energy.
• What occurs when a force acts in the opposite direction to an object's motion?


  The force causes the object to lose kinetic energy.
• How does friction affect a car traveling forward?


  Friction acts as a resistive force, taking kinetic energy away from the car and transferring it to thermal energy in the road.
• What happens to a ball thrown upward when gravity acts on it?

  Gravity pulls the ball downwards, causing it to lose kinetic energy and transfer it to gravitational potential energy.
• What happens when the ball reaches its highest point?

  The ball stops moving as all its kinetic energy is transferred to gravitational potential energy.
• What happens when gravity gives the ball back its kinetic energy?


  The ball falls back down towards the ground.
• What is the key takeaway regarding work, forces, and kinetic energy for exams?


  The main thing to understand is that work is an energy transfer that happens when a force moves an object through a distance.
• What are the types of energy transfers that can happen because of work?

  • Kinetic energy transfer when an object moves in the direction of a force.
  • Elastic potential energy transfer in a slingshot.
  • Chemical energy transfer from fuel to a shuttle.
  • Thermal energy transfer due to friction.
  • Gravitational potential energy transfer when an object is thrown upward.
• What are the main concepts related to forces and motion for exams?


  • Forces can change the motion of objects.
  • Forces can make objects move, stop, speed up, slow down, or change shape.
  • Work is a transfer of energy caused by a force moving an object through a distance.