Question

An object of mass 5 kg is acted upon by a force that varies with position of the object as shown. If the object starts out from rest at a point x = 0, what is its speed at x = 50 m?

• A. $12.2m{s}^{-1}$
• B. $18.2m{s}^{-1}$
• C. $16.4m{s}^{-1}$
• D. $20.4m{s}^{-1}$

Answer 1

The correct option is A $12.2m{s}^{-1}$

Change in kinetic energy = work done
= Area under F - x graph
$\therefore \frac{1}{2}\times 5\times v^2=10\times 25+\frac{1}{2}\times 25\times 10$
$=375$
$\therefore v=12.2m/s$.