Question

A particle starts with a velocity 2m/sec and moves on a straight-line track with retardation $0.1m/se{c}^2$. The time at which the particles is 15 m from the starting point would be

• A. 10 sec
• B. 20 sec
• C. 50 sec
• D. 40 sec

Answer 1

The correct option is A 10 sec

$v^2=u^2+2as$

$=4-2(2\times 0.1\times 15)$

$=4-3=1$

$\therefore v=1m/sec$

$v=u+at$

$1=2+(-0.1\times t)$

$\therefore t=10sec$