Question

The work done by a force (i+2j+3k) N, to displace a body from a point A whose position is (i+3j+k)m, to a point B with position vector (2ỉ +2j+3k)m is I a) 5 J b) 3J c) 2J d) 10 J
please answer fast​

Answer 1

Answer:

your question was these (a) 5j (b) 3j (c) 2j (d) 10j

and the right answer is (a) 5j

Answer 2

Answer:

a) 5 J

Explanation:

★ According to the question,

• Force vector → (i + 2j + 3k) N
• Point A → (i + 3j + k)
• Point B → (2i + 2j + 3k)

We know that:

   Displacement = Point B - Point A

⇒ Displacement = (2i + 2j + 3k) - (i + 3j + k)

⇒ Displacement = 2i + 2j + 3k - i - 3j - k

⇒ Displacement = i - j + 2k

Now,

   Work = (Force) . (Displacement)

⇒ Work = (i + 2j + 3k) . (i - j + 2k)

⇒ Work = {1(1)} + {2(-1)} + {3(2)}

⇒ Work = 1 + (-2) + 6

⇒ Work = 1 - 2 + 6

⇒ Work = 5 J

∴ Work done = 5 J