Question

A ball is moving with initual velocity 3i+4j and constqnt acc. 5i-3j its speed after 2 s

Answer 1

u=3i+4j......
a=5i-3j
t=2sec

v=u+at
v=3i+4j+(5i-3j).2
v=3i+4j+10i-6j

v=13i-2j

so velocity after 2 sec will be 13i-2j.

Answer 2

initial velocity (u)= 3i+4j

acc(a)=5i-3j

time(t)=2s

we know ,

v = u+at where v is the final velocity

or , v = 3i+4j+2(5i-3j)

=3i+4j + 10i-6j

= 13i -2j

since speed is not a vector we just need the magnitude and not the direction

magnitude =√(13)²+(2)²

=√169+4

=√153

=12.37 approx