Final answer:
1. Cleats or spikes on shoes make increased friction because they provide a rough surface.
2. Rolling friction is less than sliding friction.
3. Ball bearings' purpose is to create reduced friction.
4. In order for a train to move on the tracks, there must be friction between the wheels and the rails.
5. Heat shields on a spacecraft are necessary when it reenters the Earth’s atmosphere because at the high speed of entry, air will generate intense heat due to compression.
6. Crickets use friction to produce sounds or chirping.
7. Mucous on slugs is remarkable because it’s both slippery and adhesive.
8. When air molecules collide into each other, they cause friction.
Step-by-step explanation:
1. Cleats or spikes on shoes make increased friction because they provide a rougher surface.
2. Rolling friction is less than sliding friction.
3. Ball bearings' purpose is to create lower friction.
4. In order for a train to move on the tracks, there must be friction between the train wheels and the rails.
5. Heat shields on a space craft are necessary when it reenters the earth’s atmosphere because at the high speed of entry, air will compress and heat up, causing the temperature to rise dramatically.
6. Crickets use friction to produce sound.
7. Mucous on slugs is remarkable because it’s both lubricating and adhesive.
8. When air molecules collide into each other, they cause friction.
11. Different types of shoes are designed with specific bottom surfaces to maximize grip and safety. The bottom surfaces of sports shoes often have patterns or spikes for enhanced traction, helping the wearer maintain stability during movement, especially in competitive sports. In dry conditions, these features assist in improving grip between the shoe and the ground, whereas in wet conditions, the tread patterns help to channel water away from the surface, reducing the risk of slipping.
12. Height may vary slightly depending on the time of day due to the compression of spinal discs from gravitational force throughout the day, which may result in a person being slightly shorter by the evening.
13. Squirrels have a body structure that allows them to withstand falls from heights that would be harmful to humans. They have a low body mass relative to their size and can spread their limbs to increase air resistance, slowing down their fall, unlike humans, who have a much larger mass in proportion to their body size and would thus impact the ground with much greater force.