My science teacher said that there is no equivalent unit to a newton
Answer:
option (c) is correct
Explanation:
Half life of a substance is the time in which the element becomes half of is initial value.
half life, T = 8 days
Amount remaining, N = 10 % of original value
Let the original value is No.
N = 10% of No
N = 0.1 No
Let the time taken is t and the decay constant is λ.
The relation between the decay constant and the half life is given by
Us the equation of radioactivity
Taking natural log on both the sides, we get
0.08664 t = 2.303
t = 26.6 days
The total distance traveled by the body is the sum of the distance it traveled for the first five seconds which is 10 m and that of the next five seconds which is 30 meters. Thus, the total distance traveled is 40 m. Dividing this by the time, will give the average speed. The average speed is therefore, 4 m/s. The answer is letter C.
Answer: Option B
Explanation:
Rocks contains pores and spaces in them in which water gets trapped, and this causes the rock to break as water increases its volume due to freezing. This rocks are then eroded and are carried away into the streams and channels. The rivers and streams can carry particles of various shapes and size, which are further transported and deposited at a different place.
This particles or sediments then gets compacted and lithified in due course of time, and forms sedimentary rocks.
Water is also needed to undergo metasomatism process, that creates a metamorphic rock.
Hence, water flow is also an important driving force in rock cycle, along with tectonic activities.
Thus, the correct answer is option (B).
Answer: The size of the whale can be estimated by using echo Sounder or Sonar
Explanation:The researchers and physicst uses the knowledge of reflection of sound in water or echo to solve a lot of puzzle under water , including calclulating the distance and size of objects like fish,sunk ship,etc
The sonar is able to receive the signals from the whales and the succesive echoes that follows when placed in a strategic position in the water in the path of the whale .
The sonar has a traducers which has both a transmitter and a receiver,so it receives pulses from the whale and transmit back same echo back to the whale and to the bottom of the sea.
Using the speed of sound underwater and time taken for succesive echoes of pulses ,it can calculate with the precision the location of the whale while the image of the whale is also capture by the traducers to determine the size.
