Một vật có khối lượng 75g được ném lên từ độ cao 1,1m so với mặt đất với tốc độ 12m/s. Khi nó đạt độ cao2,1m thì tốc độ của nó là 10,5m/s. a/ Tính công đã thực hiện trên vật bởi trọng lượng của nó?b/ Cơ năng của vật bị tiêu tán bởi lực cản của không khí?

Which surface feature of the moon is characterized by mountainous areas? terrae craters maria regolith

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by

Explain the difference between each pair of concepts. a. frequency and relative frequency b. percentage and relative frequency a. select the correct choice below. a. frequency is the total number of observations in a data set. relative frequency is the number of times a particular distinct value occurs. b. frequency is the number of times a particular distinct value occurs. relative frequency is the ratio of the frequency of a value to the total number of observations. c. frequency is the total number of observations in a data set. relative frequency is the ratio of the number of times a particular distinct value occurs to the frequency. d. frequency is the number of times a particular distinct value occurs. relative frequency is the ratio of the frequency of two different values.