Pedro uses a bar magnet to pick up a nail. He then touches the tip of the nail to some staples. Why do some of the staples stick to the nail?

The nail and the bar magnet are now both permanent magnets.

ANSWER***The nail has become a temporary magnet, while the bar magnet remains a permanent magnet.

The nail has become a permanent magnet, while the bar magnet has become a temporary magnet.

The nail and the bar magnet are now both temporary magnets.

the total distance traveled by the car is

30km + 49km = 79 km .

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.