新人求助一个简单问题，很着急，帮帮忙吧大神们

class Mover {
PVector location;
PVector velocity;
// Acceleration is the key!
PVector acceleration;
// The variable topspeed will limit the magnitude of velocity.
float topspeed;
Mover() {
location = new PVector(width/2,height/2);
velocity = new PVector(0,0);
acceleration = new PVector(-0.001,0.01);
topspeed = 10;
}
void update() {
//[full] Velocity changes by acceleration and is limited by topspeed.
velocity.add(acceleration);
velocity.limit(topspeed);
//[end]
location.add(velocity);
}
// display() is the same.
void display() {}
// checkEdges() is the same.
void checkEdges() {}
}
想用加速度做一个小汽车的模型，按键盘向上箭头的时候车加速行驶，按向下箭头的时候刹车
跪求大神帮忙 ，小车模型什么样的都可以