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DSST Physical Sciences: Mechanics

Subjects : dsst, science
Instructions:
  • Answer 30 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. In a closed system - angular momentum is constant. This conservation law mathematically follows from continuous directional symmetry of space (no direction in space is any different from any other direction). See Noether's theorem. The time derivativ






2. Conservation of momentum is equivalent to the fact that the physical laws do not depend on...






3. A mechanical device that changes the direction or magnitude of a force. In general - they are the simplest mechanisms that provide mechanical advantage (also called leverage). Usually the term refers to the six classical simple machines which were de






4. When a particle is thrown obliquely near the earth's surface - it moves along a curved path. Such a particle is called projectile. The analysis of motion associated with a projectile is known as projectile motion. The path followed by a projectile is






5. The force of gravity is the force exerted by the gravitational field of a massive object on any body within the vicinity of its surface. This force is dependent on three factors: the mass of the massive object - the mass of the smaller body - and the






6. A simple machine is an elementary device that has a specific movement (often called a mechanism) - which can be combined with other devices and movements to form a machine. Simple machines are the '______________' of more complicated machines.






7. Is the rate of doing work or the rate of using energy - which are numerically the same. If you do 100 joules of work in one second (using 100 joules of energy) - the power is 100 watts = Work/Time






8. In physics - circular motion is a movement of an object along the circumference of a circle or rotation along a circular path or a circular orbit. It can be uniform - that is - with constant angular rate of rotation (and thus constant speed) - or non






9. In scientific contexts - mass refers loosely to the amount of 'matter' in an object (though 'matter' may be difficult to define) - whereas weight refers to the force experienced by an object due to gravity.[1] In other words - an object with a mass o






10. The mutual forces of action and reaction between two bodies are equal - opposite and collinear.






11. States that if no external force acts on a closed system of objects - the momentum of the closed system remains constant. One of the consequences of this is that the center of mass of any system of objects will always continue with the same velocity






12. Linear momentum or translational momentum (pl. momenta; SI unit kg






13. Friction is the force resisting the relative motion of solid surfaces - fluid layers - and material elements sliding against each other. When surfaces in contact move relative to each other - the friction between the two surfaces converts kinetic ene






14. A special kind of momentum is 'angular momentum'. This is when the object spins around and around like a top instead of going straight like the baseball or the car. Again - bigger things and faster things are harder to stop. In space - nebulae - star






15. In the physical sciences - Pascal's principle of transmission of fluid-pressure states that 'pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (init


16. The velocity of a body remains constant unless the body is acted upon by an external force.


17. Combining length and time will give the ________ of change of position. It is the basis of describing motion in terms of speed and velocity.






18. The acceleration a of a body is parallel and directly proportional to the net force F and inversely proportional to the mass m - i.e. - F = ma.






19. Lever - Wheel and axle - Pulley - Inclined plane - Wedge - Screw






20. Refers to an activity involving a force and movement in the directon of the force. A force of 20 newtons pushing an object 5 meters in the direction of the force does 100 joules of work = F(force) * d (distance)






21. Is the capacity for doing work. You must have energy to accomplish work - it is like the 'currency' for performing work. To do 100 joules of work - you must expend 100 joules of energy.






22. The location of a specified object. To defined a position of an object - we must give a reference point or location. If an object changes its position - then the motion has occurred. If an object is undergoing a continuous change in position - then






23. Archimedes' principle is a law of physics stating that the upward force (buoyancy) exerted on a body immersed in a fluid is equal to the weight of the amount of fluid the body displaces. In other words - an immersed object is buoyed up by a force equ






24. An artificial satellite orbiting the Earth at constant height - a stone which is tied to a rope and is being swung in circles - a car turning through a curve in a race track - an electron moving perpendicular to a uniform magnetic field - and a gear






25. The tendency of a force to rotate an object about an axis - fulcrum - or pivot. Just as a force is a push or a pull - a torque can be thought of as a twist to an object - a measure of the turning force on an object such as a bolt or a flywheel. For e






26. States that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time. For an isolated system - this law means that energy can change its location within the system - and that it c






27. Periodic motion - in physics - motion repeated in equal intervals of time. Periodic motion is performed - for example - by a rocking chair - a bouncing ball - a vibrating tuning fork - a swing in motion - the Earth in its orbit around the Sun - and a






28. Circular motion is ____________ even if the angular rate of rotation is constant - because the object's velocity vector is constantly changing direction. Such change in direction of velocity involves acceleration of the moving object by a centripetal






29. In fluid dynamics - Bernoulli's principle states that for an inviscid flow - an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy - longer path = faster moving air = les


30. The unbalanced torque on a body along axis of rotation determines the rate of change of the body's angular momentum - where L is the angular momentum vector and t is time. If multiple torques are acting on the body - it is instead the net torque whic