# Physics Work and Energy Question?

## A 1000 kg car is moving along a straight road at $25 m {s}^{-} 1$. A net force of 200 N acts in a forward direction for a distance of 1.0 km. What is the work done on the car by the net force?

Jun 24, 2018

$W = F x = 200 \cdot 1000 = 2 \cdot {10}^{5} \text{ J}$

Jun 24, 2018

$2 \cdot {10}^{5} \setminus \text{J"=200,000 \ "J}$

#### Explanation:

Work done is given by the equation:

$W = F \cdot d$

where:

• $W$ is the work done in joules

• $F$ is the force applied in newtons

• $d$ is the distance moved in meters

We got: $d = 1 \setminus \text{km}$. Let's convert that to meters. We know that one kilometer is equal to $1000$ meters.

So, we get:

$d = 1 \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{km"*(1000 \ "m")/(color(red)cancelcolor(black)"km")=1000 \ "m}}}}$

So the work done is:

$W = 200 \setminus \text{N"*1000 \ "m}$

$= 200 , 000 \setminus \text{N m}$

=200,000 \ "J" \ (because 1 \ "N m"-=1 \ "J")