Question

4 - Rese neck all boxes The person idey example, "concur The person only ider variable should not be ten jessed Step 5 - Definitions Compare their definitions of validity and with the ones listed here? Are they concise Validity: Validity refers to the extent than measure. (Tool specific focused on accur Reliability: Reliability determines whether af measures (FO din consistent results, the sar 8. Gravity Ranking Task cach show two rocky asteroids with masses (m). Description: The figures below (A Each show two rocky s o units, separated by a distance (dl. also expressed in arbitrary units expressed in arbitrary units, separated by a m - 10 m = 3 m= 10 m= 20 Copyright 2005 Conceptual Astronomy and Physics Education Research (CAPER) Team University of Arizona

Answer 1

(A) Ranking Order: Greatest 1_E_2_B_3_C_4_A_5_D_Least • Explanation: o Noting that the distance between the asteroids in each pair is the same, the ranking can be made based on the amount of mass that each pair of asteroids has, so two large asteroids exert a strong gravitational force on each other and two small asteroids exert a weak gravitational force on each other. o the strength of the gravitational force Fg=Gmlm2/r2, the two masses multiply together (they don't add) (B) Ranking Order: Greatest 1_E_2_B_3_C_4_A_5_D_Least • Explanation: o From Newton's Third Law, the force on the asteroid on the left by the asteroid on the right has to be exactly equal in strength to the force exerted by the asteroid on the right by the asteroid on the left. o So the ranking from Part A and Part B must be identical.