Tolong jawab in dong

Nomor 1.
Yang diketahui :
A = 5 satuan
B = 3 satuan
@ = 60°

Yang ditanya selisih kedua vektor

R^2 = A^2 + B^2 – 2 AB [email protected]
R^2 = (5)^2 + (3)^2 – 2. 5.3 cos 60
R^2 = 25 + 9 – 30 (1/2)
R^2 = 34 – 15
R^2 = 19
R = akar (19) => Jawaban C.

Nomor 2.
Yang diketahui :
F1 = 5 N
F2 = 5 N
R = 5 N

Yang ditanya sudut (@)

Pembahasan.

R^2 = F1^2 + F^2 + 2F1. F2 cos @

5^2 = 5^2 + 5^2 + 2 5^2 cos @

Anggap X = 5^2,

X = X + X + 2X cos @
X = 2X + 2X cos @

X – 2X = 2X cos @
– X = 2X cos @

Cos @ = – X/2X
Cos @ = – 1/2
Cos @ = cos 120

@ = 120° => Jawaban D

Nomor 3.

Apabila besar Resultan dan selisih dua Vektor adalah sama maka, sudut apitnya….

X^2 = A^2 + B^2 – 2AB cos @

Y^2 = A^2 + B^2 + 2AB cos @

A^2 + B^2 + 2 AB cos @ = A^2 + B^2 – 2AB cos @

[email protected] = – cos @

Cos @ = – 1 x cos @

Dimana cos 180 = – 1
Cos @ = cos (180 – @)

@ = 180 – @
[email protected] = 180
@ =180/2
@ = 90° => Jawaban C.

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Mapel : Fisika
Materi : Penjumlahan Vektor.