Bantu jawab soal-soal esainya

Scientists must learn about Mars' atmosphere before anyone attempts to go there.
A rubber ball could be dropped from the satellite.
The ball would contain a radio transmitter.
The radio would signal the rate which the ball was slowed down and the scientists would be able to calculate the density of the atmosphere.
Information about Mars could also be obtained by dropping a capsule containing scientific instruments on the planet's surface.