When was the triple beam balance invented

What kind of waves require a medium to travel? question 6 options: light waves mechanical waves all waves need a medium to travel electromagnetic waves

Organ systems work to maintain homeostasis by creating energy to allow systems to function, releasing hormones to create or end body reactions, and eliminating waste to prevent illness. t or f

69. air frictionthe velocity of the satellitea. decreases b. increases c. sometimes increases sometimedecreases d. no effect at all70. the unit of gravitational potential energy isa. jouté b. watt c. newtond. pascal71. which of the following is not influenced by a magneta. cobalt b. copper c. irond. nickel72. one joule of work done in one second by unit positive chargea.1 watt b.1 volt c.1 js d. none73. the most deviated colour of light after passing through a prisea. violet b. red c. green d. yellow4. a coin is placed below a beaker fill with water upto 12 cm isdisplaced by water isa. 9cm b.6cmс.3cmd.7cm