diff --git a/src/bodies/box2d_collision_object.cpp b/src/bodies/box2d_collision_object.cpp
index 47dc3b6..a52b14a 100644
--- a/src/bodies/box2d_collision_object.cpp
+++ b/src/bodies/box2d_collision_object.cpp
@@ -286,13 +286,13 @@ Vector2 Box2DCollisionObject::get_center_of_mass_local() const {
 }
 
 double Box2DCollisionObject::get_inverse_mass() const {
-	if (mass_data.mass <= 0) {
+	if (mass_data.mass <= b2_epsilon) {
 		return 0;
 	}
 	return 1.0 / mass_data.mass;
 }
 double Box2DCollisionObject::get_inverse_inertia() const {
-	if (mass_data.I <= 0) {
+	if (mass_data.I <= b2_epsilon) {
 		return 0;
 	}
 	return 1.0 / mass_data.I;
diff --git a/src/shapes/box2d_shape_convex_polygon.cpp b/src/shapes/box2d_shape_convex_polygon.cpp
index 036478d..73190d1 100644
--- a/src/shapes/box2d_shape_convex_polygon.cpp
+++ b/src/shapes/box2d_shape_convex_polygon.cpp
@@ -59,6 +59,9 @@ float compute_polygon_area(Vector<Vector2> points) {
 		int j = (i + 1) % points.size();
 		area += points[j][0] * points[i][1] - points[i][0] * points[j][1];
 	}
+	if (area <= b2_epsilon) {
+		area = b2_epsilon;
+	}
 	return area / 2.0f;
 }
 
diff --git a/src/spaces/box2d_sweep_test.cpp b/src/spaces/box2d_sweep_test.cpp
index 66f3b14..e9a02ad 100644
--- a/src/spaces/box2d_sweep_test.cpp
+++ b/src/spaces/box2d_sweep_test.cpp
@@ -28,6 +28,9 @@ real_t SweepTestResult::safe_fraction() {
 	b2Vec2 projection = (b2Cross(separation, motion_normal)) * motion_normal;
 
 	float safe_length = unsafe_length - projection.Length();
+	if (motion_length <= b2_epsilon) {
+		motion_length = b2_epsilon;
+	}
 	float safe_fraction = safe_length / motion_length;
 	if (safe_fraction <= b2_epsilon) {
 		return 0;