Concept Development Practice Page

20-1

Gases

1. A principle difference between a liquid and a gas is that when a liquid is under pressure, its

volume

(increases) (decreases) (doesn't change noticeably)

PHYSICS

and its density

SIGHS

(increases) (decreases) (doesn't change noticeably)

When a gas is under pressure, its volume

(increases) (decreases) (doesn't change noticeably)

and its density

(increases) (decreases) (doesn't change noticeably)

1

2. The sketch shows the launching of a weather balloon

at sea level. Make a sketch of the same weather balloon 1

when it is high in the atmosphere. In words, what is

different about its size and why?

1

1

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.