Question

main ideas: 1. position 2. motion 3. pushes and pulls 4. friction brainpop quiz: complete the following questions after watching the video 1. what is true about all forces? a. they are unbalanced b. they involve more than one object c. they cause objects to move d. they cancel each other out 2. what does the measurement unit n stand for? a. net force b. newton c. neutrino d. net weight 3. which two components must a vector quantity have? a. magnitude and velocity b. acceleration and direction c. force and speed d. direction and magnitude 4. if the net force on an object is zero, what can you conclude? a. the object is not accelerating b. the object is not touching anything c. the object is not moving d. the object is slowing down 5. which one of these arrows best corresponds to the force of drag? 6. what can you infer about an object moving at a constant velocity? a. no forces are acting on it b. gravity is exerting the strongest force on it c. the forces acting on it are in balance d. it is stationary 7. acceleration occurs when an object is subjected to a(n): a. force b. balanced force c. unbalanced force d. contact force 8. what is true of non - contact forces? a. they are always stronger than contact forces b. they always drive two objects farther apart c. they become weaker with distance d. they can not make two objects touch 9. if you drop an egg off of the empire state building, which of the following things will happen first? a. drag will increase b. the egg will appear to hover c. gravity and drag will fall into balance d. the net force will be zero 10. which of the following statements is always true? a. an object at rest has no forces acting on it b. unbalanced forces lead to a change in speed or direction c. gravity always leads to an unbalanced force d. the net force on a moving object can never be zero

Explanation:

1. Forces are interactions between objects, so they involve more than one object.
2. The unit of force is the Newton, symbol - N.
3. Vector quantities have both magnitude and direction.
4. According to Newton's second law ($F = ma$), if $F_{net}=0$, then $a = 0$.
5. Drag force acts in the opposite direction of motion.
6. An object moving at a constant velocity has zero acceleration, so the forces acting on it are in balance.
7. Acceleration occurs when an unbalanced force acts on an object according to Newton's second law.
8. Non - contact forces like gravity and electromagnetic forces decrease with distance.
9. When an egg is dropped, initially gravity causes it to fall and as it moves, drag starts to act and increase.
10. Unbalanced forces cause a change in an object's speed or direction according to Newton's second law.

Answer:

1. B. They involve more than one object
2. B. Newton
3. D. Direction and magnitude
4. A. The object is not accelerating
5. a (assuming the arrow pointing opposite to the car's motion direction)
6. C. The forces acting on it are in balance
7. C. Unbalanced force
8. C. They become weaker with distance
9. A. Drag will increase
10. B. Unbalanced forces lead to a change in speed or direction