A pulley system is used at a dock to lift shipments of fish off a boat. If you apply a force of 100 N to the pulley, it pulls the shipment with a force of 830 N. a. What is the mechanical advantage of the pulley? b. The pulley has an efficiency of 80%. If you perform 600 J of work, how much useful work does the pulley do?

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