Ðộng cơ phản lực hoạt động trên cơ sở sự bảo toàn xung lượng của hệ hai vật.

One form of energy can be another type of energy. a. created to form b. transformed into c. destroyed and then created to form

Atorque acting on an object tends to produce a. equilibrium b. rotation c. linear motion d. velocity e. a center of gravity

The brightest star in the night sky in the northern hemisphere is sirius. its distance from earth is estimated to be 8.7 light years. a light year is the distance light travels in one year. light travels at a speed of 3.00 × 108 m/s. calculate the distance from earth to sirius in miles. (1 mi = 5280 ft) g