Calculating Force of Car and Driver at Rest

[Ryo124]

Homework Statement

A car starts from rest at a stop sign and accelerates to speed 15m/s in a time of 6 seconds. The mass of the car is 300kg and the mass of the rider is 100kg. What is the force on the rider?

Homework Equations

I figured the acceleration to be 2.5m/s/s. And I know that F = ma.

The Attempt at a Solution

I'm not sure if you calculate the force on the car and the driver (400kg), or just the force on the driver (100kg).

So the equation is either F=(100)(2.5) or F=(400)(2.5). Which one? Do the car and driver act as one mass?

 

[Dick]

It asks for "the force on the rider". Not the car.

 

[Ryo124]

I just thought that the driver was in system with the car, so their masses would add up? Is that ever the case?

 

[Dick]

If they ask you for the total force you need to push the car AND driver (i.e. how much force does the engine need to provide) then you would add them.