Answer:
Muscles can also receive messages from the brain when the body temperature decreases. They respond by shivering. Shivering causes the muscles to contract and relax quickly. This process generates heat.
Newton's Second Law of Motion says that acceleration happens when a force acts on a mass. Riding your bicycle is a good example of this law of motion at work.Your leg muscles pushing pushing on the pedals of your bicycle is the force. When you push on the pedals, your bicycle accelerates.