Question

A particle has initial velocity (3 i + 4 j ) and has acceleration (0.4 i + 0.3 j ). Its speed after 10 seconds is a) 7 units b) 72 units c) 8.5 units d) 10 units

Answer 1

1) in X direction velocity =3i and acceleration =.4i
v = u +at
$v = 3 + (.4 \times 10)$
=7i
similar in y direction u =4j and a = .3j
$v =4 + (.3 \times 10)$
v=7j
v= (7i+7j) =
$\sqrt{{7}^{2} + {7}^{2}}$
= 9.8999= 10