She can put chalk in vinegar as the vinegar will disintegrate the chalk chemically demonstrating chemical changes. But for physical changes she can break the chalk into small pieces by smashing it with something or her hand.
High pressure
Low oxygen
Darkness
Answer:
a. Doppler and transit observations.
Explanation:
By means of the dopler effect, the radial velocity of an extrasolar planet can be measured, this is achieved by observing Doppler shifts in the spectrum of the star around which the planet orbits. This measure, combined with the transit observations, makes possible determine the density of the planet.
Well, in order to figure out the answer is to divide until you figure out how many miles they went per second. If it takes 5 seconds to reach 50 miles per hour it took 10 seconds per every 10 miles meaning each mile took 1 second. (Not actually possible but the answer) So, If it finished a 100 mile trip in 2 hours it took an hour for 50 miles. If it took 1 hour for 50 miles divide 60/50 which gets you 1.2 so it took 1.2 miles per minute meaning the car went 120 miles per hour I believe. I hope this helps :)
