Category Archives: A-level Units
These are 10 multiple choice questions on the topic of Gravitation according to the Singapore-Cambridge A-level Physics exams (syllabus 9646). Try it out to test your understanding of the topic. Worked solutions are provided at the end of the quiz.
Congratulations - you have completed Gravitation.
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As decreases by half and increases to 4 times, the overall effect is that is doubled.
Hence, if we approximate the change in gravitational potential energy as the boy jumps to be , his maximum height is halved.
Kinetic energy increases and gravitational potential energy increases
Kinetic energy increases and gravitational potential energy decreases
Kinetic energy decreases and gravitational potential energy increases
Kinetic energy decreases and gravitational potential energy decreases
What is the net force on each star?
- 4 kJ
- 8 kJ
+ 4 kJ
+ 8 kJ
the gravitational force acting on him is zero.
the centripetal force he experienced is zero.
the satellite’s acceleration is the same as his.
the acceleration he experienced is zero.
I was just discussing the different definitions that some JCs give for the definition of the Tesla (the SI unit for magnetic flux density) with my JC2 students last week. According to the 'A' level examiners, they are looking for something more like:
The magnetic flux density of a magnetic field is said to be 1 Tesla, if the force acting per unit length on an infinitely long conductor carrying a current of 1 A and placed perpendicularly to the magnetic field is 1 N m-1.
Rather than what is found in some A-level guide books:
A tesla is the magnetic flux density if a force of 1 N acts on a wire of length 1m, carrying a current of 1A placed perpendicular to the magnetic field.
Some JCs still teach this erroneous definition in their lectures.
So, why is the second definition wrong? In the measurement of a tesla, if we refer only to a wire of finite length, due to the end effects, the magnetic flux density at both ends of the wire will not be the same as that in the middle.
I will be addressing this error and more in my upcoming June holiday Physics intensive workshop meant for JC1 and JC2 students. Do sign up early to avoid disappointment!
The Cartesian diver is a simple toy that you can build at home using the simplest items such as a pen cap and plastic bottle. Using this toy, you can learn about upthrust and buoyancy.
When the plastic bottle is squeezed, the pressure compresses the air in the pen cap and the amount of upthrust decreases until it is less than the weight of the pen cap as less water is displaced. Hence, the pen cap sinks.
When it is released, upthrust increases to its original amount again and the pen cap floats again.
Follow this link http://www.scienses.com/cartesian-diver/ for a detailed explanation and video demonstration. It's done by my good friend who is also a JC physics lecturer!