Answer:
A) Speed
Explanation:
The medium of transmission(air) does not change before and after reflection. The sound still travels in air after the reflection. i.e the medium of transmission of sound is constant.
Since the medium of transmission remains constant, speed also remains constant. Speed only changes when the medium of transmission changes.
Energy = mass * SHC * temp change
Temp change = energy/SHC * mass
42kJ - 42000J (convert kJ to J as energy is counted as J/kg)
Temp change = 42000/4200*10
= 1C
So it goes up by 1C thus the final temperature would be 26C
Or a more logical way to think of it would be that if it takes 4200J to heat up 1kg of water by 1C (SHC is 4200J/kgC) it would take ten times the amount of energy to heat up 10kg of water by 1C hence it takes 42000J.
Answer:
Explanation:
Here h=36m, a=g=10m/s, u=0
Use s=ut+(1/2)at^2
36=0*t+(10t^2)/2
time=2.68 sec
As from the formula of final velovity, v=(2gh)^1/2
v=(2*10*36)^1/2
v=(720)^1/2
v=26.83………This is the final velocity
<span>a = (v2 - v1)/t= acceleration formula
a = (70 - 0)/7
a = 10 km/hr/sec
-----
It's better to use as few units as possible.
10 km/hr = 10 km*1000 m/km/(1 hr*3600 sec/hr) = 25/9 m/sec
a= 25/9 m/sec/se</span>