A hiker sees a lightning flash; 18 s later he hears the sound of the thunder. Recalling from his study of physics that the speed of sound in air is approximately (1/3) km/s. Calculate the distance of lightning flash. [ Assume that speed of sound is negligible as compared to speed of light] (7 pts)

An object is 10. cm from the mirror, its height is 3.0 cm, and the focal length is 2.0 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1.33 -1.33 +0.75 -0.75

Which two particles are found in the center of an atom

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.