# A car moving at 70 km/hr has a mass of 1700 kg. What force is necessary to decelerate it at a rate of 40 cm/s/s?

##### 1 Answer

Apr 19, 2018

#### Explanation:

Ref: Newton's 2nd Law commonly written

The acceleration is -40 cm/s/s. (I added the negative sign to the given deceleration rate because the acceleration is in the direction opposite the velocity.) That data needs to be converted to have units of

Plugging our data into

Minus sign indicate that force is in opposite direction.

I hope this helps.