Question

HELP!! Question number 12 from the following link. http://myclass.peelschools.org/sec/11/22607/Lessons/2.%20Dynamics/Review%20Chapter%202.pdf

Answer 1

\[m_1=2kg\]
\[m_2=4kg\]
a Use Newton's second law:
\[F_net=ma\]
\[(m_1+m_2)a=F_{net}=m_2g\]
\[a=2*9.81/6=3.27m/s^2\]
b. Now Fnet will be:
\[m_2g-F_{friction}=2*9.81-2=17.62N\]
\[a=17.62/6=2.94m/s^2\]

Answer 2

How did you go from "F = ma" to "(m1+m2)a = Fnet = m2g" ?

Answer 3

in F=ma, F is net force acting on the system, here if you write the equation for two objects your total mass is m_1+m_2 and F_net is the gravitational force that acts on hanging object

Answer 4

Okay so I understand how you got the /6 part in "a=2∗9.81/6" but i don't get how you got 2*9.81 :s

Answer 5

Wait, does Fnet = 4kg * 9.8?

Answer 6

that is gravitational force that pulls the hanging object which has mass of 2kg

Answer 7

dont you mean m1*g? since the 2kg is the one hanging?

Answer 8

you are right

Answer 9

so that is the average force? (Fnet)

Answer 10

m_1=4kg; m_2=2kg from left tot right

Answer 11

oh alright

Answer 12

you put it the other way in the answer

Answer 13

I made mistake

Answer 14

so, 2*9.8 = average force, which is Fnet??

Answer 15

yes. generally they call it net force instead of average

Answer 16

oh, i was taught that net meant average. anyways, thanks so much for your help! :D

Answer 17

you are welcome,