NIMCET 2018 Mathematics PYQ — Forces and are acting on a particle and displaced it from the poi… | Mathem Solvex | Mathem Solvex
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NIMCET 2018 — Mathematics PYQ
NIMCET | Mathematics | 2018
Forces 4i^−3j^+7k^ and −2i^+2j^−8k^ are acting on a particle and displaced it from the point (5, 7, 1) to (2, 5, -6), then the work done by the force is
Choose the correct answer:
A.
25
B.
9
C.
15
(Correct Answer)
D.
7
Correct Answer:
15
Explanation
Concept: The work done by the force is given as follows: W=F⋅d
Here, F is the force vector and d is the displacement vector.
Calculation: Net force acting on the particle is calculated as follows: F1=4i^−3j^+7k^ and F2=−2i^+2j^−8k^
F=F1+F2
F=2i^−j^−k^
Displacement vector is calculated as follows:
d=(2−5)i^+(5−7)j^+(−6−1)k^
⇒d=−3i^−2j^−7k^
Now,
W=F⋅d
W=(2i^−j^−k^)⋅(−3i^−2j^−7k^)
=−6+2+7
=3J
Explanation
Concept: The work done by the force is given as follows: W=F⋅d
Here, F is the force vector and d is the displacement vector.
Calculation: Net force acting on the particle is calculated as follows: F1=4i^−3j^+7k^ and F2=−2i^+2j^−8k^