hanhan2005

2 năm trước

vật trượt từ mf nghiêng cao 0.8m, dài 2m, g=10m/s2. bỏ qua ms giữa vật và mf nghiêng. đến mf ngang vật trượt với hệ số ms = 0.2 . tính a, a trên mf nghiêng b, v trên mf nghiêng c, t cđộng trên mf nghiêng d, a trên mf ngang e, s đi được trên mf ngang f, t cđộng trên mf ngang giúp mình với ạ, mình cảm ơn

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doanminhphuong342

2 năm trước

Đáp án:

a) 4

b) 4m/s

c) 1s

d) -2

e) 4m

f) 2s

Giải thích các bước giải:

a) Gia tốc trên mặt phẳng nghiêng:

\(a = 10.\dfrac{{0,8}}{2} = 4m/{s^2}\)

b) Vận tốc cuối mặt phẳng nghiêng:

\(v = \sqrt {2al} = \sqrt {16} = 4m/s\)

c) Thời gian chuyển động:

\(t = \dfrac{v}{a} = 1s\)

d) Gia tốc trên mặt phẳng ngang:

\(a' = - 10.0,2 = - 2m/{s^2}\)

e) Quãng đường đi được:

\(s = \dfrac{{ - {v^2}}}{{2a'}} = 4m\)

f) Thời gian chuyển động:

\(t' = \dfrac{v}{{a'}} = 2s\)

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