It would be water because if you freeze it than you will still be able to see it and if you boil it than you will be able to see it disappear.
Answer:
The efificiency is 0,25 of the machine (25%). See the explanation below
Explanation:
We calculate the efficiency with this formula:
Efficiency = energy obtained/energy supplied= 300 Joule/1200 Joule
Efficiency= 0,25
Efficiency(%) = 0,25 x100 = 25%
As we know that reaction time will be

so the distance moved by car in reaction time



now the distance remain after that from intersection point is given by

So our distance from the intersection will be 100 m when we apply brakes
now this distance should be covered till the car will stop
so here we will have


now from kinematics equation we will have



so the acceleration required by brakes is -2 m/s/s
Now total time taken to stop the car after applying brakes will be given as



total time to stop the car is given as

Answer:
Da=(1/4)Db
Explanation:
t = Time taken
u = Initial velocity
v = Final velocity
s = Displacement
a = Acceleration due to gravity = 9.81 m/s²
When s = Da, t = t

When s = Db, t = 2t

Dividing the two equations

Hence, Da=(1/4)Db
<span>The answer should be the vegitation. </span>