The Law of Conservation of Mechanical Energy states that when gravity is the only external force acting on an object the total mechanical energy of the object is zero. Question 5 options: TrueFalse
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It states that when only conservative forces (like gravity) act on an object, the total mechanical energy (sum of kinetic and potential energy) remains constant. Show more…
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When an object is solely under the influence of conservative forces, the sum of its kinetic and potential energies does not change. True False
Shaiju T.
'What is Law of Conservation of Mechanical Energy? A Total Amount of Mechanical energy in a closed system in the absence of external forces remains constant: B. Total momentum before collision is equal to total momentum after collision_ Energy will not be wasted because potential energy can be converted into kinetic energy and vice versa. D. Either A or € E: No answer'
Penny R.
i) Mechanical energy is the sum of potential energy and kinetic energy in an object that is used to do work. ii) The principle of the conservation of mechanical energy states that the mechanical energy in a system remains constant as long as the only forces acting are conservative. iii) Frictional force is a non-conservative force. Which of the following statements below is false? a) For the motion of a cart on a frictionless inclined plane, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy. b) For the motion of a cart on an inclined plane having a coefficient of kinetic friction of 0.5, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy. c) Assuming a constant gravitational potential energy for a cart, the work done by a net force on the cart equals the change in its kinetic energy. d) In an ideal free fall, the magnitude of the change in gravitational potential energy equals the magnitude of the change in gravitational potential energy. 2. In the motion of an object on an inclined plane, the initial position of the object has a height yi and the final position of the cart has a height yf. The initial velocity of the object is vi and the final velocity is vf. Assuming no friction, which of the statements or relations below is false? a) vf = 0 if and only if vi = 0. b) The mechanical energy at t=0 (initial) is 1/2mvi^2 + mgyi. c) If vf = 0, then mgyf = 1/2mvi^2 + mgyi. d) 1/2 mvi^2 - 1/2 mvf^2 = mgyf - mgyi. 3. How much work is required to stop a 1500 kg car moving at a speed of 20 m/s? a) -25,000 J. b) Infinite. c) -600,000 J. d) None listed. e) -300,000 J. 4. Based on details in the lab manual regarding procedures for the lab, the part II: Work-Kinetic Energy Theorem. Which of the statements is false? a) The unit of work is Joules (J). If we use SI base unit, then the unit of work is Kg.m^2s^-2. b) The work done by external net force can be represented by the area under the speed/displacement curve. c) We will zero the force sensor on the cart before hooking on any string. d) The work done by external net force can be represented by the area under the force/displacement curve.
Sri K.
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