A force (10i + 4j)N acts on a body of mass 2kg which is at rest. Find the velocity after 3 seconds.
-
A.
((frac{5i}{3} + frac{2j}{3})ms^{-1}) -
B.
((frac{10i}{3} + frac{4j}{3})ms^{-1}) -
C.
((5i + 2j)ms^{-1}) -
D.
((15i + 6j)ms^{-1})
Correct Answer: Option D
Explanation
Recall, (F = mass times acceleration implies acceleration = frac{force}{mass})
= (frac{10i + 4j}{2} = (5i + 2j) ms^{-2})
= (v = u + at implies v text{at 3 seconds} = 0 + (5i + 2j times 3))
= ((15i + 6j) ms^{-1})