Two friends decide to pull a fridge on skids that masses 90 kg. Alice suggests they pull together on the same rope. Bob thinks they will do better if they pull on separate ropes at an angle. The diagram below shows their two ideas (Image 1: Bob's idea, Image 2: Alice's idea) Both can pull with a force of 100 N.

a) How much net force on the fridge will result from Alice’s method?

b) How much net force on the fridge will result from Bob’s method?

c) Given the answers above which is the better way to pull the fridge in order to get maximum force on the fridge?

d) If we pull using the best method (from part (c) ) what will be the acceleration of the fridge? [Assume no friction].

e) Now let’s assume there is frictional force. Assume Bob and Alice get the fridge going at a constant speed. How much frictional force is there?

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.

answerscientific theory;

the right answer is 0.3 meters per second

the force represented by vector a is normal force. if the hockey puck is moving to the right, when it is hit with a significant force by the hockey stick the puck will move off in a different direction. correct on edge.