Exam (elaborations)
PHYS 273 –QUIZ Questions and Answers with complete solution
- Course
- PHYS 273
- Institution
- Concordia University ( )
PHYS 273 –QUIZ Questions and Answers with complete solution
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PHYS 273 –QUIZ QUESTIONSLESSON 1: Introduction to Energy
● If you double the speed of an object how does its kinetic energy change?
o It quadruples (4x)
● If the temperature of an object increases, the thermal energy…
o Always increases
● The energy stored in coal is an example of…
o Chemical energy
● Dino and Jake are out for a walk together pushing their strollers. They each exert the
same amount of force on their strollers. Dino walks twice as far as Jake. Compare work.
o Dino does twice as much work as Jake.
● The energy due to an object’s motion is called…
o KE (kinetic energy)
● Energy is…
o The ability to do work
● The sun’s energy reaches Earth in the form of…
o Electromagnetic energy
● You pick up an apple up off the ground and lift it up one meter to the top of a table. What
is happening?
o Increase the apple’s gravitational potential energy (GPE)
● The energy carried by light is called…
o Electromagnetic energy
● A joule is…
o The work done by one newton of force acting over one meter
● The metric unit of energy is…
o Joule
● You try to pick up your mom’s car but it is too heavy and it doesn’t move. After you are
very tired. Is work done or not done and why?
o No work is done on the car because it did not move
● Work is….
o The transfer of energy
● Mass being converted to energy is an example of…
o Nuclear energy
● The “c” in E=mc^2 refers to…
o The speed of light
● T or F: Saying “the electromagnetic spectrum” is the same as saying “visible light”.
o False
● The energy due to the motion of atoms in a material is…
o Thermal energy
● A calorie is…
o The amount of energy requires to raise the temperature of 1g of water by 1oC.
● T or F: All electromagnetic radiation is visible light
○ False
LESSON 2: Energy Transfer and the Conservation of energy
● T or F: For the Law of Conservation of Energy work, we must turn off lights, heaters, etc.
when we leave the house.
o False
, ● T or F: In an isolated system energy can be transformed from one form to another, but
the total energy in the system must stay constant.
o True
● Clothes dryer consumes 2500W of energy. In 2s how much energy does the dryer use?
o 5000 joules
● You lift a cat from the ground up to a shelf 2 meters above the ground. Which is a
description of the energy flow?
o Chemical energy to GPE
● A laser is powered by a battery and is used to heat up a spot on a piece of paper. What
is the energy flow?
o Chemical to electric to electromagnetic to thermal
● Which of the following is closest to being an isolated system?
o A very well insulated, opaque cooler
● You are camping & you start a wood fire & use it to boil some H2O in a pot. Flow of En?
o Chemical to Thermal
● Plants need light in order to grow. They use the process of photosynthesis for this. What
is the energy transfer involved?
o Electromagnetic to Chemical
● The Law of Conservation of Energy
o Is a fundamental law of physics with no known exceptions.
● T or F: In a system which is NOT isolated the total amount of energy must stay constant.
o False
● A ball is rolling down a hill and gaining speed. What is happening?
o The ball is losing potential energy and gaining kinetic energy
● A chair is sliding across a rough horizontal floor. The chair starts with 100J of KE and
slows down and comes to a stop. What happened to the KE of the chair?
o The KE was transformed into heat due to friction with the floor
● T or F: If the total energy of a system increases this does not necessarily mean that
energy was added to the system.
o False
● T or F: According to the Law of Conservation of Energy if solar panels use the sun’s
energy in Arizona, then there will be less solar energy for us to use in Canada.
o False
● Which is not a unit of Power?
o Joules
Your little sister drops a bag of candy on your head from the roof of your house. Right
before it hits your head it is moving quickly. Describe the candy’s En, from roof to head.
o The candy has lost potential energy and gained kinetic energy.
● T or F: Home appliances that produce heat tend to be low power.
o False
LESSON 3: Thermodynamics, Heat Engines, Power Generations
● Generators convert ….
○ Mechanical energy to electrical energy
● Heat engines convert…
○ Thermal energy to mechanical energy
● If the engine in your car produces 30 joules of useful work for every 100 joules of
gasoline used, what is its efficiency?
○ 30%
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