An 67-kg jogger is heading due east at a speed of 2.3 m/s. A 70-kg jogger is heading 61 ° north of east at a speed of 1.3 m/s. Find (a) the magnitude and (b) the direction of the sum of the momenta of the two joggers. Describe the direction as an angle with respect to due east.

Respuesta :

Answer

given,

mass of jogger  = 67 kg

speed in east direction = 2.3 m/s

mass of jogger 2 = 70 Kg

speed  = 1.3 m/s  in  61 ° north of east.

jogger one

[tex]P_1 = m_1 v_1 \hat{i}[/tex]

[tex]P_1 = 67 \times 2.3\hat{i}[/tex]

[tex]P_1 = 154.1 \hat{i}[/tex]

[tex]P_2 = m_2 v_2 \hat{i} +m_2 v_2 \hat{j} [/tex]

[tex]P_2 = 70\times v cos \theta \hat{i} +70\times v sin \theta \hat{j} [/tex]

[tex]P_2 = 70\times 1.3 cos 61^0 \hat{i} +70\times 1.3 sin 61^0\hat{j} [/tex]

[tex]P_2 = 44.12\hat{i} +79.59\hat{j} [/tex]

now

P = P₁ + P₂

[tex]P = 198.22 \hat{i} +79.59 \hat{j} [/tex]

magnitude

[tex]P = \sqrt{198.22^2 + 79.59^2}[/tex]

[tex]P =213.60 kg.m/s[/tex]

[tex]\theta = tan^{-1}\dfrac{79.59}{198.22}[/tex]

[tex]\theta = 21.87[/tex]

the angle is [tex]\theta = 21.87[/tex] north of east