# Physics 11 help ?

1. Jan 11, 2009

### roxxyroxx

Physics 11 help plz?!?

1. The problem statement, all variables and given/known data

a 1 200 kg car accelerates uniformly along level ground from rest to a speed of 80 km/h in 10 s. what is the power output of th motor?

2. Relevant equations

eff=(mgh/f*d)x100%
p=f*v

3. The attempt at a solution
idk where 2 start...

2. Jan 11, 2009

### rock.freak667

Re: Physics 11 help plz?!?

Seeing as how the car goes from rest to 80 km/h in 10 s, what is the acceleration produced by the car and hence the force produced by the car?

3. Jan 11, 2009

### roxxyroxx

Re: Physics 11 help plz?!?

a=2.2m/s^2
so what formula do i use?

4. Jan 11, 2009

### NBAJam100

Re: Physics 11 help plz?!?

Did you learn that P=W/t? where W=work and t=time?

About the a= 2.2m/s^2, i didnt check the number, but if you know the acceleration, and you know the mass. Then use F=ma

5. Jan 11, 2009

### roxxyroxx

Re: Physics 11 help plz?!?

ok so F=2640N and W=F*d so what's d?

6. Jan 11, 2009

### rock.freak667

Re: Physics 11 help plz?!?

Use the second equation you put in the relevant equations section.

7. Jan 11, 2009

### NBAJam100

Re: Physics 11 help plz?!?

Yeah, you are making it harder on yourself if you use P=W/t, i was just bringing it up as another method to use at some point. You already know P=f*v and you have f and v