you wont see it animate, maybe try animating the view instead of moving it instantly.
Place this in viewDidAppear to see it after the view has come on the screen.
[UIView animateWithDuration:0.3f
animations:^{
hammer.center = CGPointMake(hammer.center.x, hammer.center.y + 12);
} completion:^(BOOL finished) {
[UIView animateWithDuration:0.3f
animations:^{
if (CGRectIntersectsRect(hammer.frame, floor.frame)) {
hammer.center = CGPointMake(hammer.center.x , hammer.center.y -50);
}
}];
}];