Physics 2

• What is difference between a scalar and a vector quantity?

  Scalar quantities have magnitude only, vector quantities have magnitude and an associated DIRECTION
• Describe the relationship between extension and force applied

  Extension is directly proportional to the force applied (up to the limit of proportionality)
• Define contact and non-contact forces

  Contact forces; objects are physically touching

  Non contact; the objects are physically separated
• What is the difference between distance and displacement?

  Distance is how far something moves (not including direction). Displacement is measured in a straight line from start point to finish point and includes direction
• Give the equation for weight, include units

  Weight (N) = mass (kg) x gravita field strength (N/kg)
• What is the difference between speed and velocity?

  Speed is scalar. Velocity is a vector (includes direction)
• What is meant by resultant force?

  The remaining force when forced in all directions have cancelled each other out
• Give the equation for calculating speed

  Speed = distance/ time
• Give the equation for work done, include units

  Work done (J) = force (N) x distance (m)
• Give the equation for spring constant, include units

  Force (N) = spring constant (N/m) x extension (m)
• Give the equation for acceleration, including units

  Acceleration (m/s^2) = change in velocity (m/s) / time taken (s)
• Define stopping distance

  The sum of the distance travelled during drivers reaction time and the distance travelled under the braking force
• What is the acceleration of a falling object Earth?

  9.8 m/s^2
• State factors that may affect a persons reaction time

  Tiredness, drugs, alcohol and distractions, speed
• State Newton’s first law

  If the resultant force on an object is zero and the object is stationary, it will remain stationary. The object is moving it will continue to move at the same velocity
• State factors that may affect a vehicle's braking distance

  Adverse road and weather conditions. Poor condition of vehicle. Speed
• Define inertia

  The tendency of objects to remain in their state of rest or uniform motion
• What is the relationship between kinetic energy and work done by the brakes?

  The work done by the brake is equal to the reduction in kinetic energy
• State Newton’s second law

  The acceleration of an object is proportional to the resultant force acting on the object, and inversely proportional to the mass of the object (F=ma)
• Give the equation for momentum

  Momentum = mass x velocity
• State Newton’s third law

  Whenever two objects interact the forces they exert on each other are equal and opposite
• What is meant by the conservation of momentum?

  In a closed system, the total momentum before and event is equal to the momentum after
• Define transverse waves

  The oscillations are perpendicular to the direction of travel
• Why does a light ray change direction during refraction?

  Due to the change in wave speed
• Define longitudinal waves

  The oscillations are parallel to the direction of travel
• How do electromagnetic waves affect a circuit?

  EM waves may induce an alternating current in a circuit
• Define the period of a wave

  Time taken for one wave to pass a given point, Period = 1/ frequency
• How are atoms affected when they absorb EM radiation?

  Electrons jump up an energy level
• Give the wave speed equation, state the units

  Wave speed (m/s) = frequency (Hz) x wavelength (m)
• Which 3 times of wave can harm human body tissues?

  Ultraviolet, X-ray, Gamma-ray
• List the sections of the electromagnetic spectrum

  Radio waves, microwaves, infra red, visible light, ultra violet, x-rays, gamma rays
• List the uses of each part of the electromagnetic spectrum

  Radio waves: TV and radio

  Microwaves: satellite communications and cooking food

  Infra red: electrical heaters, cooking good and infra red cameras

  Visible light: fibre optic communications

  Ultra violet: energy efficient lamps, sun tanning

  X-rays and gamma: medical imagining and treatments
• List the properties of electromagnetic waves

  All travel at 3x10^8 m/s, all can be transmitted, absorbed, refracted, reflected
• Name the poles of a magnet

  North and South
• How do like poles interact?

  They repel
• Describe the motor effect

  When a current flows through a wire, a magnetic field is produced around the wire. Shaping the wire into a solenoid (coil) increases the strength of the magnetic field. When the wire is placed inside a magnetic field a force is exerted on the wire
• How do unlike poles interact?

  They attract
• Give the unit for magnetic flux density

  Tesla, T
• Name the area of force around a magnet

  Magnetic field
• Describe Flemings left hand rule

  Thumb, first finger and second finger are held mutually at right angles. The thumb points in the direction of the motion (force), the first finger in the direction of the magnetic field, the second finger in the direction of the current