1,

I. `m_1*a` = F-K

II. `m_2*a` = K

I.: a = `(F-K)/m_1`

II. `m_2*(F-K)/m_1` = K

`m_2*F-m_2*K` = `m_1*K`

`m_2*F` = `(m_1+m_2)*K`

K = `(m_2*F)/(m_1+m_2)` = `(3*8)/(3+2)` = `24/5` = 4,8 N

Ábra


2,

I. `m_1*a` = `F-K_1-mu_m_1*g`

II. `m_2*a` = `K_1-K_2-mu*m_2*g`

III. `m_3*a` = `K_2-mu*m_3*g`

I. 10a = `100-K_1-0.1*10*10` = `90-K_1`

II. 7a = `K_1-K_2-0.1*7*10` = `K_1-K_2-7`

III. 3a = `K_2-0.1*3*10` = `K_2-3`

III. `K_2` = 3a+3

I. `K_1` = 90-10a

II.

7a = 90-10a-3a-3-7 = 80-13a

20a = 80

a = 4 `m/s^2`

I. : `K_1` = `90-10*4` = 90-40 = 50 N

III: `K_2` = `3*4+3` = 15 N

Ábra