In an ecosystem, why can only one species fill an ecological niche?

A teacher does 140 j of work in 20 s. How much power in watts did he use? Show your work.

We have an object with a density of 620g/cm^3 and a volume of 75cm cm^3. What is the mass of this object

What is the initial speed of water if it rises to the height of 171m

Which of the following would NOT be a cause of beach erosion? A. Restricting sand supply to the beach. B. Building sea walls. C. Fine weather and calm waves in summer. D. Severe winter storms and heavy waves in winter.

Select the statement that correctly represents how light travels. A. Light cannot travel in a vacuum when the light source is moving. B. Light cannot travel in a vacuum if the light source is stationary. C.

A 100 N box is placed on an inclined plane that makes a 30° angle with the horizontal. Calculate the component of gravitational force that acts down the inclined plane. A. 25 N B. 50 N C. 87 N D. 100 N

Approximately how many kelvins are equal to 60 c? a. 289k b. 323k c. 333k d. 413k

What are two ways to change velocity?

What is the main optical element of a refracting telescope?

Two water manometers are connected to a tank of air. One leg of the manometer is open to 100kPa pressure (absolute) while the other leg is subjected to 90kPa. Find the difference in deflection between both manometers, Delta h_a - Delta h_b.