Answer:
18kcal
Explanation:
Melting enthalpy of water: 80 cal/g
The melting enthalpy discribes how much heat is needed to melt a substance. So you get the heat by multiplying the mass of your substance with its melting enthalpy.
225g*18cal/g=18000cal=18kcal
Answer:0.61 m
Explanation:
Given
Initial velocity (u)=7.40 m/s
launch angle 
height of fence=0.7 m
Trajectory of Projectile is given by
For x=2.1 m
At x=2.1 m Y=1.31
therefore Fox clear fence by a margin =1.31-0.7=0.61 m
The answer is the third graph
Answer:
Maximum height of rocket = 2538.74 m
Explanation:
We have equation of motion s = ut + 0.5 at²
For first 5 seconds
s = 0 x 5 + 0.5 x 40 x 5² = 500 m
Now let us find out time after 5 seconds rocket move upward.
We have the equation of motion v = u + at
After 5 seconds velocity of rocket
v = 0 + 40 x 5 = 200 m/s
After 5 seconds the velocity reduces 9.8m/s per second due to gravity.
Time of flying after 5 seconds

Distance traveled in this 20.38 s
s = 200 x 20.38 - 0.5 x 9.81 x 20.38² = 2038.74 m
Maximum height of rocket = 500 +2038.74 = 2538.74 m
Answer:
Explanation:
The thermal efficiency of a Power cycle 
where;




--- (1)
---- (2)
The coefficient of performance is:

let replace the value of
in the above equation then;



The
On the other hand, the heat pump

By replacing equation (1) into the above equation; we have:



t