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QUESTION 6 The definition of relativistic momentum is the (A) momentum of an object when measured in a Newtonian frame of reference. (B) momentum of an object when measured regardless of its frame of reference. (C) momentum of an object when measured in the frame of reference in which the object is in motion. (D) momentum of an object when measured in the frame of reference in which the object is stationary.
QUESTION 16 According to the theory of special relativity the concept of simultaneity is best described as (A) when two events occur at the same time. (B) when an observer sees two events occurring at the same time. (C) two events observed to happen at the same time in a particular frame of reference. (D) the relation between two events assumed to happen at the same time when observed from any frame of reference.
QUESTION 23 (2 marks) Twin astronauts conduct an experiment where one travels with a velocity close to the speed of light to a distant planet while the other stays on Earth. Each twin expects the other to be a different age by the time the first twin reaches and remains on the distant planet. Use the theory of special relativity to explain why the twins will no longer be the same age and draw a conclusion about which twin will be younger.
QUESTION 24 (4 marks) A spaceship travelled from Planet A to Planet B at a speed of 0.90c. An observer that was stationary relative to both planets measured the time taken for the trip to be 4.0 years. Calculate the time taken for the trip as measured by an observer on the spaceship.
QUESTION 1 (1 mark) Explain why an object with mass cannot travel at the speed of light in a vacuum.
QUESTION 3 Identify the correct formula for the massenergy equivalence relationship. A) E= me? (B) E=mgh ©) E=Lime? 2 (D) E= %mv2
QUESTION 10 Proper length is the length measured in the frame of reference where the object is (A) atrest. (B) 1n motion. (C) accelerating. (D) 1n motion but not accelerating.
QUESTION 19 A spaceship with a velocity of 9.0 X 10 m s! is measured to be 125 m in length by an observer at rest. Calculate the length of the spaceship as measured by somebody on board the spaceship. (A) 119m (B) 131 m (C) 137m (D) 178 m
QUESTION 15 An objects velocity can only be measured relative to (A) a fixed reference frame. (B) the speed of light. (C) an object at rest. (D) an observer.
QUESTION 22 (2 marks) A collection of mesons was observed by a detector to move an average distance of 11.0 m when travelling at 95% of the speed of light. However based on their properties the mesons were expected to travel an average distance of 3.4 m. Explain the difference between the observed and expected average distances.
QUESTION 1 (2 marks) Two spaceports are stationary relative to each other. Astronaut A moves from one spaceport to the other at relativistic speed and observes the lights on both spaceports turn off at the same time. Astronaut B is at a stationary position equally distant relative to each spaceport and observes the lights turn off one after the other. Explain why the astronauts view these events differently.
QUESTION 3 Select the option that contains the two correct postulates of special relativity. (A) The laws of physics are the same in all inertial frames of reference and the speed of light in a vacuum has the same value c in all inertial frames of reference. (B) The laws of physics are the same in all inertial frames of reference and the relation between two events is assumed to happen at the same time in all inertial frames of reference. (C) The relation between two events is assumed to happen at the same time in all inertial frames of reference and the laws of physics are not the same in all inertial frames of reference. (D) The relation between two events is assumed to happen at the same time in all inertial frames of reference and the speed of light in a vacuum has the same value ¢ in all inertial frames of reference.
QUESTION 8 Which of the following is a correct consequence of the speed of light in a vacuum being the same for all observers? (A) The frame of reference of the observer is always the real frame of reference. (B) Observations of events in distant galaxies are observations of events that occurred in the past. (C) A clock that is moving relative to an observer will tick faster than a clock that is at rest in the observers own frame of reference. (D) When measured by a stationary observer the length of a moving object is smaller than the length of the object when it is measured in its own frame of reference.
QUESTION 11 A rocket with a velocity of 0.9 ¢ journeys from Earth to a distant planet. An observer on Earth measures the journey to have taken 3.00 years. Calculate the time taken for the journey as measured by a clock on the rocket. (A) 0.95 years (B) 1.31 years (C) 6.88 years (D) 9.48 years
QUESTION 8 (8 marks) A ladder measured at 20 m in length when stationary is carried horizontally by Observer A at a velocity of 0.9 c through a barn. The barn is 15 m long and has an open door at either end. Observer B sitting in the barn presses a button when they see that the ladder has completely entered the barn. Observer B sees both the front and rear barn doors instantaneously close and then open again at the same time the button is pressed. Explain how this could be viewed as a paradox and conclude whether the ladder will make contact with the barn doors. Support your explanation and conclusion with calculations.
QUESTION 1 An object is unable to accelerate to the speed of light because (A) length contraction will change the height of the object. (B) time dilation will decrease the velocity of the object. (C) the object will gain infinite momentum. (D)_ the inertia of the object will decrease.
QUESTION 16 A train is travelling at relativistic speed and is about to move through a tunnel. An observer on the train measures the train and tunnel to each be 95 m long. A second observer is stationary relative to the tunnel. They would observe the train to (A) simultaneously enter and exit the tunnel. (B) decrease its mass while in the tunnel. (C) move faster while in the tunnel. (D)_ be shorter than the tunnel.
QUESTION 17 The half-life of an unstable subatomic particle is measured by a stationary detector to be longer when its velocity approaches the speed of light. This is because the particle (A) is moving relative to its frame of reference. (B) isin the same frame of reference as the detector. (C) experiences time differently relative to the detector. (D) cannot be accurately observed at relativistic speeds.
QUESTION 25 (3 marks) An observer who is stationary relative to a moving spaceship measures the velocity of the spaceship to be 2.0x108 ms . Calculate the length of the spaceship if the observer records it as 18 m. Show your working. Length = m (to two significant figures)
QUESTION 1 (3 marks) Describe the effects of relativistic travel on an object.
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