Why a control is needed in a valid experiment

According to the theory of island biogeography, which of the following is not an island ecosystem? a. A mountain with thriving vegetation surrounded by an arid desert. b. The open ocean. c. Grasslands that surround a lake. d.

What causes a ray of white light to split into seven colors when passed through a prism? A. refraction B. reflection C. filtering D. absorption

half life worksheet answer key 3. What percent of a sample As-81 remains un-decayed after 43.2 seconds

A geologist finds four layers of sedimentary rock. She determines that no geologic events have shifted the layers. She labels the layers A, B, C, and D from the top to the bottom. Which statement about these layers is accurate?

A coin of mass m is placed on top of a horizontal turntable a distance R from the axis of rotation. Gravity is acting vertically downward with magnitude mg and the normal force on the coin from the turntable is acting vertically upward.

A football travels 25 m in 2.5 seconds. What is the speed of the football?

A 25 kg ball is thrown into the air when thrown it's going 10 m/s calculate how high it travels

As part of a circus performance, a man is attempting to throw a dart into an apple which is dropped from an overhead platform. Upon release of the apple, the man has a reflex delay of 215 milliseconds before throwing the dart.

A train travels 90 kilometers in 1 hour, and then 82 kilometers in 5 hours. What is it's average speed?

3. A hydraulic lift is used to jack a 950-kg car 45 cm off the floor. The diameter of the output piston is 23 cm, and the input force is 375 N. a. What is the area of the input piston? (10pts) b.