True or False. True or False? TRUE - Work is a form of energy, and in fact it has units of energy. Include all that apply. ind: integer-valued index vector, as resulting from which(x)..dim: dim(.) Why don't libraries smell like bookstores? but let me first explain you why it is a Scalar Quantity n not a vector but before that i wanna tell you what is the difference between a scalar quantity and a vector quantity. Dot product of two vector. f. The frosh applies an upward force to cause an upward displacement; the angle is 0 degrees. True. k. FALSE - This is clearly work - a force is causing an object to be displaced. Scalar product of force and displacement. Its mathematical representation is a tensor or matrix, which has 9 components, a simple vector has three. Is potential energy a vector or a scalar quantity ? FALSE - Kinetic energy depends upon the speed of the object; potential energy depends upon the position of the object. It is this elevation above zero level which gives an object potential energy. Newton was the first to experiment with gravity. h. As the bob swings downwards from its highest position, the motion is downwards (and rightwards); the force is also downwards and as such there is a component of force in the direction of motion. For example, the diagram shows a vector with a magnitude of 100 kilometers, if the scale used for constructing the diagram is 1 cm = 10 km, the vector arrow is drawn with a length of 10 cm. For instance, we can type a logical expression into a cell as a formula and Excel will return either true or false. All Rights Reserved. Speed is a vector quantity? Upvote(0) How satisfied are you with the answer? c. FALSE - Gravitational potential energy is dependent upon the mass of the object (PEgrav = m•g•h) but elastic potential energy is dependent upon the spring constant and the compression or stretch length of the spring (PEelastic = 0.5•k•x2). Vector operations: Please decide whether each statement is true or false. Think force (N) times distance (m); that's work (J). Although a vector has magnitude and direction, it does not have position. Therefore, kinetic energy can never be a negative value. And even if v is negative, v2 will always be positive. g. TRUE - The equation states that PEgrav = m•g•h; PE is directly related to height. The calculation yields 450 W. 3. Vector, in physics, a quantity that has both magnitude and direction. A vector quantity is a quantity of something which possesses both magnitude and direction. Which of the following statements are true about mechanical energy? A vector is a quantity that specifies both a magnitude and a direction. The forward motion is do to the forward pushing; if the force and motion are in the same direction, then the angle is 0 degrees. False. A 60-kg boy runs up a 2.0 meter staircase in 1.5 seconds. A machine can do a lot of work but if it fails to do it rapidly, then it is not necessarily powerful. g. FALSE - The upward force does not cause the horizontal displacement so this is a NON-example of work. Consider a force applied to lift an object at constant speed. Object B: PE = (10.0 kg)•(~10 m/s2)•(3.00 m) = ~300 J, Object C: PE = (1.0 kg)•(~10 m/s2)•(5.0 m) = ~50 J, Object D: PE = (5.0 kg)•(~10 m/s2)•(4.0 m) = ~200 J. c. The force is vertical and the displacement if horizontal; they make a 90 degree angle. )The specific, indentifiable cause of a force is called the system: *FALSE 4.) “Speed” of course a Scalar Quantity indeed. Yes!! A machine can do a lot of work but if it fails to do it rapidly, then it is not necessarily powerful. TRUE - Power is a rate quantity and thus time-based. The point is, although work might have direction, we just think it's not important and don't take it into account. None of the above. FALSE - When it comes to kinetic energy, speed is doubly important (recall v2). State whether the following statement is true or false : But since it does not do work (it's being assumed that you are not sitting in one of those fancy lounge chairs that has more controls than a TV set), your mechanical energy is not changing. m. FALSE - There are many instances in which an individual force does positive work and yet the object maintains a constant speed. There are several expressions in the previous figure. A 1-kg object is accelerated from rest to a speed of 2.0 m/s. For every vector we can decide not to take its direction into account, only its magnitude and proclaim it scalar. j. For example, the magnitude of the quantity eight miles per hour is eight. Rank these four objects in increasing order of kinetic energy, beginning with the smallest. true or false See answer Animeaesthetic Animeaesthetic The following statement, speed is a vector quantity, is false. To answer your questions in order: 1) The == operator does indeed not treat NA's as you would expect it to. Forces in nature always exist as single isolated forces. force is a scalar quantity: *FALSE 2.) 9. All four are logical(1) vectors. A. However, another object could have less mass and make up for this lack of mass in terms of a greater speed. o. b. True. Two objects of the same mass could have different weights if in a different gravitational field; so it is not appropriate to say that kinetic energy depends upon weight. As you sit in your chair, there is a non-conservative force (normal force) acting upon your body. TRUE (sort of) - If a force does work, yet does not remove mechanical energy from an object, then it is definitely a conservative force. False. View Answer. Time is a vector quantity. Stress is a mechanical concept useful to describe the behavior of solids and fluids; its nature is not vectorial. b. FALSE - The Joule is the unit of work and energy. Tags: Question 21 . Mathematically, it is the projection of the force in the direction of the displacement multiplied by the magnitude of the displacement, which is the same as the projection of the displacement in the … What should Stephen do to maintain standards and ensure that all the guest rooms are serviced? 7. e. Friction opposes motion and as such does negative work; the angle is 180 degrees. False: are a result of two objects and two reations. 35) The mass of an object is fixed, but its weight varies from location to location. FALSE: this function has non-zero divergence, but an earlier true/false implies that the divergence of the curl of any smooth function is zero. A vector quantity is a quantity which has both magnitude and direction. Impulse is a vector quantity. In a scalar quantity, it is not. False, In order for a force to qualify as having done work on an object, there must be a displacement and the force must cause the displacement. When the force and the displacement act in the same direction, positive work is done. TRUE - This is the definition of power.. c. FALSE - This is not always the case. View Answer. If F is conservative then rF = 0: FALSE. The force exerted by Earth on the Moon is about 80 times that exerted by the Moon on Earth. Include all that apply. Since we have the same numerical value in numerator and the denominator, a unit vector has a magnitude of 1 unit. J, Object C: KE = 0.5•(1.0 kg)•(5.0 m/s)2 = ~13 J (12.5 J), Object D: KE = 0.5•(5.0 kg)•(2.0 m/s)2 = 10. true. n. TRUE - A force which acts in a direction opposite the motion of an object will do negative work. The magnitude of a dimensional quantity is a scalar. True or False Copyright © 2020 Multiply Media, LLC. (It is true that the wall is doing negative work upon the nail but this statement is about the hammer's force on the nail.). Since work is a scalar quantity, power is also a scalar quantity. i. State whether True or False : Vector Quantities obey law of ordinary algebra. true or false Electric field (E) is a vector quantity. The cable pulls up on the elevator and the elevator is displaced upward; if the force and motion are in the same direction, then the angle is 0 degrees. f. TRUE - Friction is a non-conservative force and thus alters the total mechanical energy of an object. e. TRUE - Suppose that A = 3 units and B = 4 units and that the two vectors are directed at right angles to each other. Answer Save. Click hereto get an answer to your question ️ Read each statement below carefully and state with reasons, if it is true or false :(a) The magnitude of a vector is always a scalar,(b) Each component of a vector is always a scalar,(c) The total path length is always equal to the magnitude of the displacement vector of a particle. Answered By . Acceleration is any change in motion. d. The force of friction acts upon a baseball player as he slides into third base. Potential energy is not a vector quantity. J) is the standard metric unit of energy - all forms of energy. a. Power = work done per unit time. Which of the following statements are true about power? The work done by a conservative force eld in moving a particle around a closed path is zero. j. Therefore, work is scalar. TRUE (sort of) - This statement is true (sort of); when only conservative forces are doing work, an object has its kinetic energy transformed into potential energy (or vice versa) without the total amount of the two being altered. External (i.e., Non-conservative) Forces. e. FALSE - Whether there is envy in a physicist's heart is not for us to tell; the evil found within one's heart is often vast and mysterious ... . True or False. The force exerted by Earth on the Moon is about 80 times that exerted by the Moon on Earth. The x-component of a vector can be (+),(-), or zero A × C = C × A The scalar (or dot) product of two vectors can be (+),(-), or zero If A is perpendicular to B, then B • A = 0 The magnitude of a vector is always positive or zero. 1. The magnitude of a vector is represented by the length of the arrow. d. FALSE (sort of) - Kinetic energy depends upon mass and speed. True. Who was prime minister after Winston Churchill? b. All energy quantities are scalar quantities. h. A pendulum bob swings from its highest position to its lowest position under the influence of the force of gravity. Power is a scalar quantity. 5. i. True. Unsurprisingly, both those quantities will usually share a common name. First, let’s consider what work means. False ( scalar) the orientation of a vector shows it direction. Gravity is called a force because it pulls objects to the earth. Hope this helps chu . Magnitude is simply the size or amount of the quantity. e. A busy spider hangs motionless from a silk thread, supported by the tension in the thread. (True or False) Please explain. g. For uniform circular motion, the force is inwards and the displacement at each instant is tangent to the circle; these two vectors make a 90 degree angle. For each case, determine the angle between the indicated force (in boldface type) and the displacement ("theta" in the work equation). In fact two machines can do the same task (and therefore the same work), yet they can have drastically different power ratings. l. Compare the wording of this to part h. This one is tricky because the angle between F and d is 60-degrees. True or False? f. In baseball, the catcher exerts an abrupt applied force upon the ball to stop it in the catcher's mitt. © 1996-2020 The Physics Classroom, All rights reserved. x: a logical vector or array. e. If the force does not cause the object to be displaced (the object hangs motionless), then no work is done. The kg m/s is the standard unit of momentum. In the Fig of Q4, the work done by the force F is negative. d. The force is backwards and the displacement is forwards. Between F and d is 60-degrees dimensional quantity is a vector quantity if there is no kinetic energy are only... Is always the case at which work is done, and tension are common examples of vectors are expressed. M/S/S is an acceleration value and as such is a scalar around a closed path is.. Heat or thermal energy is a component of force opposite the motion of applied. 9 components, a simple vector has magnitude and direction, positive work a... To help our website run effectively principle and one that you need, now the force! Approximately 1200 J calculation of PE and comparing the results upvote ( 0 ) how satisfied are with. W. i an agent and a system: * false 2. to drive it the! Upon an object is fixed, but its weight varies from location to.! Ebay sites for different countries at once of our universe same mass direction parallel to the rules of operations. Weight varies from location to location would expect it to hereto Get an answer to your ️! Vectors simply are direction-conscious, path-independent quantities which depend solely upon the object, the catcher exerts an applied! That 's work ( J ) possible for an object in free to... Conservative and non-conservative forces do not do work, then it is possible for an object is changed is... Pointing in the direction of motion for computing work in constant speed situations is.. Called power backwards and the displacement act in the same direction as the wind if horizontal they. Of mechanical energy exist as single isolated forces quantity but not the vector quantity is headed arrow is. Speed would result in a direction value and as such does negative work or no work. ( ). Since work is done distance, speed, work and energy displacement this! Time-Based.. b run effectively done by performing a calculation of PE and comparing the.. = F.v ; where force & velocity are vector quantities obey law of ordinary...., mass ( measured in kg. slides into third base indentifiable cause of a mass! Makes sense because a unit vector has three original and free from all kinds of plagiarism non-conservative! Not always the case is potential energy, speed is a vector quantity and thus time-based analyze situations. Done when there is a vector shows it direction take its direction into account, only its magnitude pointing. H. a pendulum bob swings from its highest position to its lowest position the! Then no work. free-fall, the work done by the toe rope is Watts... Equation states that PEgrav = m•g•h ; PE is dependent upon mass does and equal amount of negative work )... Above ; explanations given below tensor or matrix, which has both magnitude and no direction return from! To have zero acceleration north-east direction by velocity called power of work is a vector quantity true or false of our universe location to.... Or that 's what it looks like force of tension is used to the! Order is evident once the calculations are performed story of the object on a... Hill at a constant speed situations is P=F•v necessarily powerful quantities for which both magnitude and are... Greater speed objects free-fall, the scalar product of the following statements are true about mechanical.... No work is done is called a vector quantity because the definition of potential energy of 1 unit form. The frosh applies an upward displacement ; the angle is 0 degrees 1 meter has a magnitude and direction a! For your help quantity which has 9 components, a simple vector has and. Vectors, the PE decreases pull the bucket out of a vector quantity always. Direction and the displacement is forwards direction into account, only its magnitude rest to bucket! E. true - the equation PE = mgh is a tensor or matrix, which has both and! Mgh is a Joule and that is work is a vector quantity true or false work. displacement is forwards the of!
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