Question

A body lying initially at point (3, 7) starts moving with a constant acceleration of 4i. Its position after 3 s is given by the co-ordinates:

• A. (7, 3)
• B. (7, 18)
• C. (21, 7)
• D. (3, 7)

Answer 1

The correct option is C (21, 7)

The initial coordinate of the particle is $(3,7)$

x-coordinate is 3 unit

y-coordinate is 7 unit

As the body starts from rest so initial velocity$=0$

The acceleration of the body along x-axis$=4units$

The acceleration of the body along y-axis$=0$

So, after 3 seconds,

Using equation of motion along x-axis,

$x=x_0+ut+\frac{1}{2}a{t}^2$

as $u=0a=4unitst=3seconds$

$s=3+\frac{1}{2}\times 4\times 3^2=21units$

As there is no motion along y-axis so it will remain unchanged

Hence the final coordinate are $(21,7)$