Question

An aluminum block of mass m1 = 2.65 kg and a copper block of mass m2 = 8.15 kg are connected by a light string over a frictionless pulley. They sit on a steel surface as shown in the figure below, where θ = 39.0°. (See the table below for the appropriate coefficients of friction).

If the blocks move, determine the magnitude of their acceleration. (If the blocks do not move, enter 0.)

Answer 1

http://www.webassign.net/serpse7/5-table-60.gif
heres the table

Answer 2

http://www.webassign.net/serpse/p5-60.gif
heres the picture

Answer 3

what have you tried so far?

Answer 4

well im stuck because so far ive solved for the acceleration but when i replace the variables with the actual values and simplify the answer is wrong

Answer 5

if you find that it accelerates, you're going to have to use the coefficients of kinetic friction to find acceleration...

Answer 6

yes i did do that.. but it says my answer is within 10% of the correct value.. i dont know what im doing wrong

Answer 7

-T+8.15gsin39 - muk*8.15gcos39 = 8.15a
T-muk*2.65g=2.65a

Answer 8

those your equations?

Answer 9

-T+8.15gsin39 - .36*8.15gcos39 = 8.15a
T-.47*2.65g=2.65a

Answer 10

my equation is : (m2gsin39-fk2-fk1)/(m1+m2)=a

Answer 11

that'll work, if you have the right friction forces...

Answer 12

compare your values to - .36*8.15gcos39 and -.47*2.65g

Answer 13

my friction forces are fk1=12.21 and fk2=22.35

Answer 14

yep

Answer 15

the value i got for acceleration was 1.45 m/s2

Answer 16

but it still says that im incorrect

Answer 17

does my answer seem correct? or am i off

Answer 18

seems right

Answer 19

i dont know whats wrong with that problem.. i used the same exact value for acceleration to find the tension and it said i got the correct value for the tension

Answer 20

could just be a glitch.. ill tell my professor about it but thank you for your help :)