một vật có khối lượng là 30kg bắt đầu chuyển động nhanh dần đều và sau khi đi được 20cm thì có vận tcs 6km/h lực tác dụng vào là

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

Alice added sodium chloride to water and stirred the water for several minutes. alice is most likely trying to demonstrate that ionic compounds a. are hard. b. can dissolve. c. are clear. d. can melt.

Asmall metal bar, whose initial temperature was 10° c, is dropped into a large container of boiling water. how long will it take the bar to reach 70° c if it is known that its temperature increases 2° during the first second? (the boiling temperature for water is 100° c. round your answer to one decimal place.) sec how long will it take the bar to reach 98° c? (round your answer to one decimal place.)