Introductory problem about force (N)

[SamuelVictor]

Homework Statement

A car of mass 1000 kg accelerates on a straight, flat, horizontal road with an acceleration a = 0.3 m s-2 . The driving force F on the car is opposed by a resistive force of 500 N. What is the net (resultant) force on the car?

Homework Equations

F=ma

The Attempt at a Solution

0.3*1000= 300N
500N- 300N= 200N
answer is 300N... Why?

 

[Noctisdark]

Hint:
To use Newton's second law, F should be the NET force, the sum of all forces
F = m*a retry solving the equation ;)

 

[berkeman]

Homework Statement

A car of mass 1000 kg accelerates on a straight, flat, horizontal road with an acceleration a = 0.3 m s-2 . The driving force F on the car is opposed by a resistive force of 500 N. What is the net (resultant) force on the car?

Homework Equations

F=ma

The Attempt at a Solution

0.3*1000= 300N
500N- 300N= 200N
answer is 300N... Why?

The 500N number is not needed for this problem -- they just threw that into confuse you. The Net Force F is what gives the Net Acceleration a with the car having the Mass m. They ask for the Net Force and give you the Net Acceleration and mass. That's all you need. Makes sense now?

 

[SamuelVictor]

thanks that helps