Gravitational potential energy.
As the rider falls, the GPE is converted into kinetic energy.
Answer:
Explanation:
No of atoms of Ra in 1 g of sample = 6.023 x 10²³ / 226
N = 2.66 x 10²¹
disintegration constant λ = .693 / half life
half life = 1620 x 365 x 60 x 60 x 24 = 5.1 x 10¹⁰ s
disintegration constant λ = .693 / 5.1 x 10¹⁰
radioactivity dn / dt = λN
= (.693 / 5.1 x 10¹⁰ ) x 2.66 x 10²¹
= .3614 x 10¹¹ per sec
= 3.614 x 10¹⁰ / s
The two points on a periodic wave in a medium are said to be in phase if they have the same amplitude and are moving in the same direction.
Option 4.
Explanation:
A periodic wave is termed for waves which flow in a repetition pattern in a given time scale. Periodic wave can also be termed as a transverse wave. So a transverse wave have various crests and troughs. The two successive crests and two successive troughs are said to be in phase with each other.
Thus, for a periodic wave in a medium, the in phase can be obtained in two points which have the same amplitude and are moving in the same direction.
As amplitude is a scalar quantity and so direction should be taken into consideration for making the points related to successive crests only in phase with themselves. Also this also relates the points related to successive troughs to be in phase with each other. But a crest and a trough will not be in phase with each other.
Thus, option 4, that is the two points on a periodic wave in a medium are said to be in phase if they have the same amplitude and are moving in the same direction.
