Answer:
10500 J/kg/*C
Explanation:
Quantity of heat required=mass of substance x specific heat capacity x change in temperature
Quantity of heat required=0.25 x 4200 x [30-20]
Quantity of heat required=0.25 x 4200 x 10
Quantity of heat required=10500 J/kg/*C
Answer:
Explanation:
We shall convert all the displacement in vector form .
i and j represents east and north respectively .
D₁ = 4 i
D₂ = 4 j
D₃ = - 5 cos 53.1 i + 5 sin 53.1 j
= -3i + 4 j
Total displacement = D₁ + D₂ + D₃
= 4i + 4 j - 3i + 4 j
= i + 8j
magnitude of displacement = √( 1² + 8² )
= 8.06 km
velocity = 8.06 / 5
= 1.61 km / h
Direction from x axis in anticlockwise direction .
Tanθ = 8 / 1 = 8
θ = 83° north of east .
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.
Explanation:
Formula to calculate angular acceleration is as follows.
or, 
Putting the given values into the above formula as follows.
= 
= 0.326 
Thus, we can conclude that the wheel’s angular acceleration if its initial angular speed is 2.5 rad/s is 0.326 .
Answer:
1. 15.64 m/s
2. 2,354,400 seconds
Explanation:
1. 1mile is equivalent to 1609metres and 1hour is equivalent to 3600sec.
35mph = (35×1609)/3600
= 56315/3600
= 15.64 m/s
2. Note that 1 day ===> 24hrs
60min ==> 1hr
60sec ===> 1min
Thus 27.25 days = 27.25×24×60×60
= 2,354,400 seconds
