Please write in English because I do not understand
Answer:
20 J
Explanation:
Given:
Weight of the book is,
Height or displacement of the book is,
The work done on the book to raise it to a height of 2 m on a shelf is against gravity. The gravitational force acting on the book is equal to its weight. Now, in order to raise it, an equal amount of force must be applied in the opposite direction.
So, the force applied by me should be equal to weight of the body and in the upward direction. The displacement is also in the upward direction.
Now, work done by the applied force is equal to the product of force applied and displacement of book in the direction of the applied force.
Therefore, work done is given as:
Therefore, the work done to raise a book to a height 2 m from the floor is 20 J.
Answer: Yes
The capacitor in an RC circuit (Resistor-Capacitance circuit) creates a time delay that decays exponentially. Therefore when the voltage to the bulb is removed, it takes a long time for the capacitor to completely discharge.
Although the brightness of the bulb will diminish as the capacitor discharges, the bulb will still be lit until the capacitor discharges to a voltage that is too low to sustain visible light (to the human eye) from the bulb.
Shortwave radios have a higher frequency than ultraviolet light