Answer:
Option e) 320 s
Explanation:
Here, distance = 3.0 km = 3000 m
The velocity of boat when it is going upstream;
Upstream velocity = velocity of boat in still water - velocity of river flow
So, Upstream velocity 
So,Time to go upstream

The velocity of boat when it is going downstream;
Downstream velocity = velocity of boat in still water + velocity of river flow
So, Downstream velocity 
So,Time to go downstream

So, total time (t) = 
Option E is the correct answer.
Answer:
Explanation:
Volume per unit time flowing will be conserved
a₁v₁ = a₂ v₂
π r₁² x v₁ = π r₂² x v₂
(0.9 x 10⁻²)² x .35 = ( .45 x 10⁻² )² x v₂
v₂ = 1.4 m / s
Answer:
Experimental
Explanation:
Here the dependency of pressure on the temperature is to be determined. For finding this factor we need to calculate the pressure of the object at different temperature.
The process of calculating pressure for different temperature is experimental investigation because we need to perform this experiment for finding these value. On the basis of observed values the we can conclude the dependency.
Thus, this investigation is experimental.
Answer:
Distance s=ut+1/2 at^2
If it’s released then this becomes
s=1/2at^2
s=1/2 *9.81*9
s=44.1 m
Explanation: