Multiple choice, only one answer is right?

1. Three forces act at the same time on an object: 3.0 N [E]; 5.0 N [W]; and 8 N [E]. What is the net force on the object? A) 6.0 N [E] B) 6.0 N [W] C) 16 N [E] D) 16 N [W] E) 10 N [E] 2. A transport truck pulls on a trailer with a force of 800 N [E]. The trailer pulls on the transport truck with a force of A) 800 N [W], no matter what the acceleration of the truck. zero. C) 800 N [W], only if the truck is moving at a constant velocity. D) less than 800 N [W], if the truck is slowing down. E) more than 800 N [W], if the truck is accelerating. Refer to the figure below for the next question(s). A B D E 3. An object is pushed along a smooth surface with a force of 12 N [W] and 12 N [S]. The net force exerted on the object is: A) 12 N B) 24 N C) 12N [SW] D) 17 N [SW] E) 17 N [NE] 4. A box has a weight of 1500 N. Its mass is approximately A) 15 kg B) 150 kg C) 120 kg D) 1500 kg E) 15000 kg 5. A book is being pushed along a desk at a constant velocity (to the left). Which free body diagram best represents the forces acting on the book? A) B) C) D)