- #1
Omelette
- 3
- 0
Homework Statement
Q1) After a 1.30 x 10^2kg astronaut (incl. equipment) connects a safety line (length = 22.0m) to herself and to the spacecraft (mass = 2.80 x 10^3kg), she pushes against the craft and moves away at a constant velocity of 9.0m/s. How long does it take the safety line to become tight?
Q2) A 3.0kg object is pulled along a horizontal surface as shown in the diagram below by a horizontal force of 2.0N. If the object is accelerating at a rate of 1.2m/s^2, what is the force of friction acting on the object? (Diagram below).
Homework Equations
Fnet = ma
d = Vot + .5at^2
a = (Vf - Vo)/2
d = (Vf + Vo)/2 * t
Vf^2 = Vo^2 + 2ad
Ff = μFn
The Attempt at a Solution
Q1) I thought to set d = 22, Vo = 0, Vf = 9, and solve for t using the 4th equation, but that answer isn't one of the choices. I think maybe the masses of the objects need to be used, but I don't know how they may help.
Q2) I used F = ma, and so Fnet = (3)(1.2) = 5.2 N (which is also on the diagram). I thought about Fnet = Fapp - Ff, and tried to solve for Ff by subtracting Fnet from Fapp, but that isn't one of the choices as well.
I don't really know where to start with these questions.
Help would be much appreciated! Thanks!