# Racing car and frictional forces question

1. Jan 27, 2013

### dansbr

1. A racing car of mass 950kg accelerates from 30km/h to 170km/h over a distance of 220 meters. Frictional forces and wind resistance can be assumed to be 750N.

Determine the tractive force produced by the car to provide this acceleration

The car finally reaches a speed of 250km/h. Friction and wind resistance are 1900N at this speed. What power output is required is required to maintain this speed.

3. Am completely new to this type of question so any help would be greatly appreciated

2. Jan 27, 2013

### Staff: Mentor

You should at least have some elementary equations somewhere.
Can you determine the kinetic energy of an object moving with known velocity and mass?
If the car accelerates, does this change?
Can you find a relation between a change in kinetic energy and a force?

For the second part, do you know a relation between power and force?

3. Jan 27, 2013

### dansbr

so should i use KE=MV² and P=Fv

4. Jan 28, 2013

### LawrenceC

Power is force times velocity as you typed above.

The first part of the problem where you seek the tractive force can be done by either work-energy relationships or by kinematic equations such as V1^2-V2^2 = 2*a*s followed by F=m*a + friction/wind.

5. Jan 28, 2013

### Staff: Mentor

There is a factor of 2 missing in the first equation. The second equation is useful for the second part, right.