A object starts from rest at and is acted on by a horizontal force that varies with…

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

1.0\,\text{kg}

object starts from rest at

x=0

and is acted on by a horizontal force that varies with position according to

F(x)=a x^{2}

, where

a

is a constant and

x

is in meters. If the object’s speed is

4.0\,\text{m/s}

when it reaches

x=2.0\,\text{m}

, what is the value of

a

? (a)

1\;\text{N/m}^{2}

(b)

4\;\text{N/m}^{2}

(c)

3\;\text{N/m}^{2}

(d)

2\;\text{N/m}^{2}