Two particles of equal mass have velocities `vec v_1 = 2 hat im//s^-1` and `vec v_2 = 2hat j m//s^-1`. First particle has an acceleration `vec a_1= (3 hat i+ 3 hat j) ms^-2` while the acceleration of the other particle is zero. The centre of mass of the two particles moves in a path of.

Options

A. circle
B. parabola
C. straight line
D. ellipse

Answer

C

Explanation

( c) `vec v_(cm) = (m 2 hat i+ m 2hat j)/(m + m) = hat i+ hat j m//s`
`vec a_(cm) = (m(3 hat i+ 3 hat j)+m xx 0)/(m+m) = (3)/(2) hat i+ (3)/(2) hat j`
Since acceleration and velocity are in same direction, so path should be straight line.