Stop applying force to a sprite - ios

Question

In my spritekit game I am working on applying a wind like force to my game. I have somehow implemented this a number of ways.
The first way I tried is this :
Attempt one
In this code here the sprite is first pushed as it should, however I cant get it too stop.
-(void)update:(NSTimeInterval)currentTime {
NSLog(#" %d",_time);
if (_time == 200 /* | _time==400 */ ) {
[self startPush];
}
-(void)startPush
{
SKAction *startPush = [SKAction runBlock:^{
[_player.physicsBody applyForce:CGVectorMake(50, 0)];
}];
SKAction *wait = [SKAction waitForDuration:1];
SKAction *stopPush = [SKAction runBlock:^{
// [_player.physicsBody applyForce:CGVectorMake(-50, 0)];
[_player.physicsBody applyForce:CGVectorMake(0, 0)];
}];
SKAction *sequence = [SKAction sequence:#[startPush, wait,stopPush]];
[self runAction:sequence];
}
Attempt Two
I attempted to change my code since i saw this post by LearnCocos2d where he said that AKActions are bad for movements.
Constant movement in SpriteKit
So i tried this
Here also the pushing doesnt stop even if pushOn is set to No.
Would love some help in doing the final tweaks in this.
Thank you
-(void)update:(NSTimeInterval)currentTime {
NSLog(#" %d",_time);
if (_time == 200 /* | _time==400 */ ) {
windOn=NO;
}else if (_time==300)
{
pushOn=NO;
}
if (pushOn)
{
{
[_player.physicsBody applyForce:CGVectorMake(0.1, 0)];
}

Answer 1

Applying a zero force is equivalent to applying ... nothing. You're basically leaving the body as is with this code:
[_player.physicsBody applyForce:CGVectorMake(0, 0)];
Instead you probably wanted to zero the velocity vector:
_player.physicsBody.velocity = CGVectorMake(0, 0);
The difference is that applyForce acts as an "add vector" operation, whereas the line above is a "set vector" operation.