Question

A body whose mass is 120g has a velocity θ⃗ = (2î+ 5ĵ)m/s at a certain instant. Its K.E. is
a. 1.74 j b. 2.75j c. 3.75j d. 4.75j

Answer 1

Explanation:

$v = 2i + 5j \\ |v| = \sqrt{ {2}^{2} + {5}^{2} } \\ |v| = \sqrt{4 + 25} = \sqrt{29} = 5.385m {s}^{ - 1} \\ k.e = \frac{m {v}^{2} }{2} \\ k.e = \frac{5.385 \times 5.385 \times 120}{2 \times 1000} = 1.749j$