Science 8

• What does magnitude refer to in the context of forces?

  Magnitude refers to the size or strength of the force.
• In what unit is magnitude commonly expressed?

  Magnitude is commonly expressed in Newtons.
• What are the two types of forces?

  • Contact forces
  • Non-contact forces
• What are contact forces?

  Contact forces are forces where objects touch or make contact with each other.
• What is applied force?

  Applied force is a force given to a person or object by another person or object.
• What is the symbol for force?

  The symbol for force is F.
• What does frictional force do?

  Frictional force is the force against or opposite an object in contact that makes the movement of the object slow down.
• What is an example of frictional force?

  Air resistance is an example of frictional force of the air.
• What is normal force?

  Normal force is the force that acts perpendicular to the surface of the object in contact with.
• What is tensional force?

  Tensional force is the force applied to a string, rope, or chain.
• What are non-contact forces?

  • Forces where objects do not touch or contact each other
  • Act over a zone or area called a field
• What is gravitational force?

  Gravitational force is the force of attraction between two objects.
• How does gravity affect objects on Earth?

  Gravity causes objects to fall down to the ground.
• What are magnetic forces?

  Magnetic forces are forces exerted on a field of attraction or repulsion as in the case of magnets and magnetic materials.
• What are balanced forces?

  Balanced forces are forces that are equal in magnitude but opposite in direction.
• What is the effect of balanced forces on motion?

  Balanced forces do not cause a change in motion and are always at rest.
• What are unbalanced forces?

  Unbalanced forces are forces that cause a change in motion of an object.
• How do unbalanced forces differ from balanced forces?

  Unbalanced forces are not equal in magnitude but opposite in direction.
• What is net force?

  Net force or resultant force is the sum of all the forces acting on an object.
• When are two or more forces considered balanced?

  Two or more forces are balanced if their effects cancel each other.
• What does the Law of Inertia state?

  The Law of Inertia states that an object at rest remains at rest, and an object in motion will continue to move at constant velocity unless acted upon by a net force.
• What is inertia?

  The tendency of an object to maintain its state of rest or of uniform velocity in a straight line is called inertia.
• How does mass affect inertia?

  The greater the mass of an object, the harder it is to move when at rest, or difficult to stop when in motion.
• What does the Law of Acceleration state?

  The Law of Acceleration states that the acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to the object’s mass.
• What does the Law of Interaction state?

  The Law of Interaction states that for every action, there is always an equal and opposite reaction.
• What does the Law of Interaction tell us about forces?

  The Law of Interaction tells us that a force exerted on any object is always exerted back by an equal magnitude of force but in the opposite direction.
• What are action and reaction forces?

  Forces always come in pairs, which are called action and reaction.
• What is work in the context of physics?

  Work is the transfer of energy by a force acting on an object as it is displaced.
• What happens to energy when an object is lifted and then allowed to fall?

  An object absorbs energy when lifted from the ground and when allowed to fall, it loses energy.
• What is potential energy (PE)?

  Potential energy is the energy that the body gains or loses with respect to its position.
• What is kinetic energy (KE)?

  Kinetic energy is the energy of a moving object.
• What does the term "kinetic" mean?

  The word kinetic comes from the Greek word "kinetikos," which means moving.
• What does kinetic energy measure?

  Kinetic energy measures the amount of work the object can do because of its motion.
• What is the speed of sound in dry air?

  331.5 m/s
• How much does the speed of sound increase if you increase 1C°?

  0.60 m/s
• What is the value of gravity?

  9.8 m/s^2
• What is reflection?

  Turning back of the wave as it hits a barrier.
• What is reverberation?

  Multiple reflections or echoes in a certain place.
• How is sound created?

  Created when something vibrates, sending waves through the material.
• What are sound waves?

  Sound waves are longitudinal waves.