I need to mimic jumping behavior for the player in my game. Player consists of two fixtures with circle and rectangle shapes. Rectangle I use to detect ground and it is a sensor. Is some point for jumping I do this:

float impulseY = body->GetMass() * PLAYER_JUMPING_VEOCITY / PTM_RATIO * std::sin(PLAYER_JUMPING_ANGLE * PI / 180);
body->ApplyLinearImpulse(b2Vec2(0, impulseY), body->GetWorldCenter(), true);

and player does not jump. But when I do this:

body->SetLinearVelocity(b2Vec2(0, PLAYER_JUMPING_VEOCITY / PTM_RATIO * std::sin(PLAYER_JUMPING_ANGLE * PI / 180)));

my player jumps. Also when I change the rectangle shape to be normal (not sensor) shape, its works again. Why? Just in case here are the parameters of my rectangular sensor:

b2PolygonShape boxShape;
boxShape.SetAsBox(width * 0.5/2/PTM_RATIO, height * 0.2/2/PTM_RATIO, b2Vec2(0, -height * 0.4 /PTM_RATIO), 0);

b2FixtureDef boxFixtureDef;
boxFixtureDef.friction = 0;
boxFixtureDef.restitution = 0;
boxFixtureDef.density = 1;
boxFixtureDef.isSensor = true;
boxFixtureDef.userData = static_cast<void*>(PLAYER_GROUP);