Question

A body of mass 5 kg starts from the origin with initial velocity (30i+40j) m/s.if a constant force (-6i-5j) N act on the body the time in which the Y component of the velocity becomes zero is

Answer 1

aceleartion in y = -1
initial y velocity=40
therefore 
v=u-at
v=0
u=at
40=1*t
t=40sec

Answer 2

Answer:

The Y component of the velocity becomes zero in 40 sec.

Explanation:

Given that,

Mass m= 5 kg

Force F= (-6i-5j) N

Initial velocity u = (30i+40j) m/s

The acceleration of y component is

Using newton's second law

F= ma

$a=\dfrac{F}{m}$

$a=\dfrac{-5}{5}$

$a= -1\ m/s^2$

Using equation of motion

$v= u+at$

$0=40+(-1)t$

$t= 40\ sec$

Hence, The Y component of the velocity becomes zero in 40 sec.