AS Physics Help Please; Stuck on Last Two Questions

[boeing737]

Just on the last two questions of my physics homework, and I really don't understand them! They're topics we haven't covered yet, the teacher just said have a go at them but I really don't understand them.

 

1, A barge of total mass 300kg is pulled by a single rope attached to a tugboat of mass 1000kg. If the drag on the tug and the barge is one-tenth of their respective weights, and the total forward force exerted bt the tug is 5130kg force, find the magnitude of:

 

a, the total force resisting the forward motion of the tug and barge (is this just 30kg + 100kg?)

 

b, the acceleration of the tug/barge system

 

c, the unbalanced accelerating force on the barge ?

 

d, the tention in the towing rope ?

 

2, An astronaut of mass M1 = 80kg stands on the horizontal floor of a spaceship moving vertically with acceleration a. If the acceleration due to gravity on the astronaut is g = 9.81 ms^-2, write a mathematical expression for and calculate the value of the reaction force R between the astronaut and the floor of the spaceship when:

 

a, a=0

 

b, a=8 ms^-2 upwards

 

c, a=8ms^-2 downwards.

 

I really don't understand, especially the last question? Please could someone explain these to me. I spent ages on the rest of the homework trying to get it right, but these questions just tripped me up. Please help!

[Mr Skeptic]

1

a) weight is not mass. Your answer should be a unit of force.

b ) Newton's laws of motion, once you find the net force

c) consider the barge and the tug separately

d) the force somewhat holding back the tug and pulling forward the barge

 

2

If you are in an enclosed accelerating box, it is rather hard to tell the difference between acceleration and gravity. What you feel is the force with which the floor is pushing up at your feet.