Doubtly
@Doubtly · Joined Feb 2021
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- The work done on an object does not depend on .... (i) displacement (ii) applied force The work done on an object does not depend on initial velocity of the object. 1
- If we increase the velocity of a car moving on a flat surface to four times its original speed, its potential energy If we increase the velocity of a car moving on a flat surface to four times its original speed, its potential energy will not change. 1
- The total energy of an object falling freely towards the ground ... (i) decreases (ii) remains unchanged The total energy of an object falling freely towards the ground remains unchanged. 1
- The potential energy of your body is least when you are ..... (i) sitting on a chair (ii) sitting on the ground The potential energy of your body is least when you are sleeping on the ground. 1
- While dragging or lifting an object, negative work is done by (i) the applied force (ii) gravitational force While dragging or lifting an object, the negative work is done by frictional and gravitational force, respectively. 1
- Power is a measure of the ....... (i) the rapidity with which work is done (ii) amount of energy required to perform Power is a measure of the rapidity with which work is done 2
- Which of the forces involved in dragging a heavy object on a smooth, horizontal surface, have the same magnitude? The gravitational force and the reaction force in vertical direction have same magnitude. Friction is not action as the horizontal surface i... 1
- Joule is the unit of ... (i) force (ii) work (iii) power (iv) energy Joule is the unit of work and energy 2
- For work to be performed, energy must be .... (i) transferred from one place to another (ii) concentrated correct option is a For work to be performed, energy must be transferred from one place to another. 1
- Why is the work done on an object moving with uniform circular motion zero? Answer: Because the centripetal force is always perpendicular to the direction of motion, so W = Fscos 90^° = 0 . In uniform circular motion... 1
- If an object has 0 momentum, does it have kinetic energy? Explain your answer. Answer: No. If an object has zero momentum, its kinetic energy is also zero. Momentum is p = mv . The mass m of an object is never zero, so... 1
- Determine the amount of work done when an object is displaced at an angle of 30o with respect to the direction of t Answer: W = Fscos 30^° = sqrt3/2Fs ≈ 0.866 Fs When a force F acts at an angle θ to the displacement s , only the component of the force alon... 1
- Prove that the kinetic energy of a freely falling object on reaching the ground is nothing but the transformation Answer: At height h the object has potential energy mgh and zero kinetic energy; on reaching the ground its kinetic energy is also mgh, so a... 1
- A slit of width 'a' is illuminated by white light. For what value of 'a' will the first minima for red light fall A slit of width 'a' is illuminated by white light. For what value of 'a' will the first minima for red light fall at an angle of 300 2
- Derive the formula for the kinetic energy of an object of mass m, moving with velocity v. Kinetic energy is the energy possessed by an object by virtue of its motion. K.E=1/2 mV² Derivation: Let us consider an object of m which is... 1
- Explain the difference between potential energy and kinetic energy. Kinetic Energy Potential Energy (i) Kinetic energy is the energy possessed by the body due to its motion. (i) Potential energy is the energy... 1
- When to Use Internal and External JavaScript Code? Answer: Use internal JavaScript for small, page-specific code; use external JavaScript (a separate .js file) when the code is long or shared... 1
- What are Cookies in JavaScript? Answer: Cookies are small pieces of text data (name=value pairs) that a website stores in the user's browser, and JavaScript can read and wr... 1