A-2-2-kg-block-starts-from-rest-on-a-rough-inclined-plane-that-makes-an-angle-of-25-with-the-horizontal-The-coefficient-of-kinetic-friction-is-0-25-As-the-block-goes-2-m-down-the-plane-the-mechani

Question Number 24716 by Tinkutara last updated on 25/Nov/17

A 2.2 kg block starts from rest on a

rough inclined plane that makes an

angle of 25 ° with the horizontal . The

coefficient of kinetic friction is 0.25 . As

the block goes 2 m down the plane, the

mechanical energy of the Earth - block

system changes by

Answered by ajfour last updated on 25/Nov/17

△ U = m g △ y

△ K = \frac{1}{2} {m v}^{2}

△ E = △ U + △ K = W_{e x t}

= - (μ m g \cos 25 °) s

= - \frac{1}{4} \times 2.2 \times 10 \times 2 \times \cos 25 °

= (- 11 \cos 25 °) J .

\approx - 10 J .

Commented by Tinkutara last updated on 25/Nov/17

Thank you Sir!