Question

The velocity of a body of mass $20kg$ decreases from $20m/s$ to $5m/s$ in a distance of $100m$ . Force on the body is :

• A. $-27.5N$
• B. $-47.5N$
• C. $-37.5N$
• D. $-67.5N$

Answer 1

Answer: (C)

$-37.5N$

The equation of motion is given as,

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

${\left(5\right)}^2={\left(20\right)}^2+2\times a\times 100$

$a=-1.875m/s^2$

The force is given as,

$F=ma$

$F=20\times \left(-1.875\right)$

$F=-37.5N$

Thus, the force on the body is $-37.5N$.