Conceptual physics questions, just want to check my work :D?

Question

Ok so I have already worked these problems out but I'm just wondering what you guys get. Here are the problems:

Bill is in outer space on his way out of L.A. A force of 10 N pushes on Bill. Suddenly, when Bill has reached a speed of 250 mph, another 10 N force, directed opposite to the first force, also pushes on Bill. Now, with both forces acting on Bill, what happens to Bill's speed?

a) Bill will stop.
b) Bill will slow down.
c) Bill will speed up.
d) Bill will continue moving at a constant velocity.

Number 2:

Two blocks of masses 20 kg and 8 kg are connected together by a light string and rest on a frictionless level surface. Attached to the 8 kg mass is another light string which a person uses to pull both blocks horizontally. If the two-block system accelerates at 0.6 m/s^2, then what is the tension in the connecting string between the blocks?

a) 12 N
b) 6.0 N
c) 20 N
d) 4.0 N

Please provide why you feel the answer is right. Feel free to send me an IM. :)

so for the first question, you all are saying that it would be d? and for the second, itd be 12 N?

Answer 1

Hi. In problem 1 you have two balanced and opposite forces. Bill will not go faster or slower. In question 2 the 8 kg block drops out of the equation.

Answer 2

For the first question you want to calculate what's the web rigidity. the full rigidity is 10+ (-10) = 0. What takes position to a body that no rigidity act on it. evaluation the first regulation of action. For the 2d: The 20 kg mass is shifting with an acceleration of 0.6 m/s2, being pulled through the string. evaluation the 2d regulation of action. what's the rigidity once you've the mass and acceleration. perfect answer?

Answer 3

1. 10 - 10 = 0, 0/m = 0

2. F = ma = 20*0.6

Answer 4

Bill will change direction that`s all.

12N