2020

• equation linked to gravitational field strength, mass, and weight

  W=mg
• equation linked to acceleration, resultant force, and mass

  resultant force=mass $\times$ acceleration
• What is meant by elastic behaviour?

  The spring will return to its original length when the force is removed.
• Suggest 2 properties that should be the same for each spring

  -spring constant

  -original length
• vector quantity -has magnitude and a direction

  scalar quantity -has magnitude only
• The equation links to mass,momentum,velocity

  P=mv
• expalin why X-rays can be used to produce images of the bones inside the body

  X-rays are absorbed by bone but can pass through flesh.
• A student placed a magnet close to each metal sample.Describe what happened.[2 marks]

  Iron and steel will be attracted to the magnet.

  Aluminium, copper, and tin will not be attracted to the magnet.

  
• Explain what would happen if the paper clip was removed and brought close to the south pole of the permanent magnet.[2 marks]

  The paper clip would still be attracted to the magnet because of induced magnetism.

  
• Plan an investigation to determine how the height of the ramp affects the acceleration of the trolley.[6 marks]

  • Place one wooden block under the ramp.
  • Vary the height by placing a different number of wooden blocks.
  • Measure the height of the ramp using a metre ruler.
  • Measure distance travelled using ruler.
  • Measure time taken using light gates and a computer.
  • Or measure time taken using a timer.
  • Release trolley from the same position each time.
  • Release trolley without applying a force.
  • Repeat at same height and calculate a mean.
  • Repeat for different heights.
  • Calculate acceleration using a=v2−u22sa = \frac{v^2 - u^2}{2s}a=2sv2−u2​.

  
• The bowling lane is horizontal.Explain why the bowling ball decelerates as it travels along the lane.[2 marks]

  • Resistive force acts on the ball.
  • So work is done on the ball.
• Explain why the bowling ball slows down when it hits the pin.You should use ideas about momentum in your answer.[3 marks]

  • Momentum is conserved in the collision.
  • Momentum of the pin increases.
  • Therefore, momentum of the ball must decrease.
• Explain why the radiographer stands behind a protective screen when taking an X-ray image.[3 marks]

  Taking lots of X-rays would give a large dose, which would increase the radiographer’s risk.

  The screen absorbs some of the X-rays.
• Explain how electrical signals in the transmitter produce a signal in the receiver.[3 marks]

  Electric current in the transmitter produces radio waves.

  Radio waves are absorbed by the receiver, inducing electrical current in the receiver at the same frequency.

  
• Explain one other advantage of a reduced speed limit.[2 marks]

  • The car will have less kinetic energy.
  • So less likely to cause injury in the event of a collision.
• The empty van has a shorter stopping distance than the full van when driven at the same speed.Explain why.[3 marks]

  • Same maximum force applied by the brakes.
  • Because mass is less, there is a greater deceleration.
  • So braking distance is less.
• When the switch was closed, the reading on the top pan balance increased.Explain why the increased reading showed that there was an upward force on the wire.[2 marks]

  The downward force on the balance increased, therefore the wire must experience an equal and opposite force which is upwards.
• Explain how the values in Table 3 can be used to determine the size of the force on the wire.[2 marks]

  Calculate the difference between the two mass readings, then convert to kg and multiply by gravitational field strength.