Question

A body of mass 2 kg is initially moving with a velocity of 4 m/sec. Now a force of 1.25 Newtons acts for 8 sec. Then a force of 2.5 N acts for 8 sec. The final velocity of the body is

• A. 12.55 m/sec
• B. 17 m/sec
• C. 19 m/sec
• D. 25 m/sec

Answer 1

The correct option is C 19 m/sec

Acceleration produced by 1.25 N
$=\frac{F}{m}=\frac{1.25}{2}=0.625$
Acceleration produce by 2.5
$N=\frac{2.5}{2}=1.25$
$\therefore \upsilon =u+at$
$\therefore v_1=4+0.625\times 8$

$\therefore v_1=9$
$\therefore v_f=9+1.25\times 8$

$\therefore v_f=19$