Question

Particle A is moving along x-axis. At time $t=0,$ it has velocity of $10m/s$ and acceleration $-4m/s^2.$ Particle B has velocity of $20m/s$ and acceleration $-2m/s^2.$ Initially both the particles are at origin. at time $t=2s$ distance between the two particles is

• A. $24m$
• B. $36m$
• C. $20m$
• D. $42m$

Answer 1

The correct option is A $24m$

Particle A,

$u=10m/s$

$a=-4m/s^2$

$t=2$

$s=ut-\frac{1}{2}a{t}^2$

$=10\times 2-\frac{1}{2}\times \left(4\right)(2{)}^2$

$=20-8$

$=12m$

Particle B,

$u=20m/s$

$a=-2m/s^2$

$t=2s$

$s=ut-\frac{1}{2}a{t}^2$

$=20\times 2-\frac{1}{2}\times 2\times 2^2$

$=40-4$

$=36m$

$S_B-S_A=(36-12)m$

$=24m$