Question

a body of mass 6 kg is acted by a constant force (2i-3j)N.if its initial velocity at t=0 sec is (-3i+4j) .then at what time its velocity will be in x axis ?

Answer 1

Ans is 8 seconds. I hope this will help you.

Answer 2

Answer:

The velocity will be in x-axis at 8 sec.

Explanation:

Given that,

mass = 6 kg

Force F= (2i-3j) N

Initial velocity u= (-3i+4j)

Using newton's second law

F= ma

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

$a=\dfrac{2i-3j}{6}$

Using equation of motion

$v= u+at$

Final velocity v= xi

Final velocity is xi because it velocity in x-axis and y component will be zero.

$xi=(-3i+4j)+\dfrac{2i-3j}{6}t$

j components on  Left hand side is zero

$0=4+\dfrac{-3}{6}t$

$t= 8\ sec$

Hence, The velocity will be in x-axis at 8 sec.