 |
| Photo by kimfaires |
Why does the stopping puck not violate Newton's First Law? How can Newton's Second Law be used to predict the distance the puck will travel before stopping?
Wednesday, October 12, 2011
Keep Sliding
Subscribe to:
Post Comments (Atom)
The reasons that cause the puck to slow down are air resistance and friction on the ice. If there were no friction and the puck were in a vacuum, it would be in constant motion.
ReplyDeleteReettamlap is correct, Newtons first law of motion is and object in rest will stay in rest and an object in motion will stay in motion unless acted upon by an outside force. you can use the second law of motion (F=m*a) to predict the distance the puck will travel before stopping because the greater the force of the moving object (mass), the greater the distance the object at rest will move. The greater the mass of the object at rest, the less it will move. So knowing the force and mass, you would be better able to predict the distance.
ReplyDeleteThe second law states that the acceleration is dependent on two variables-the net force acting on the object, and the objects mass. Depending on these two things will help predict the distance the puck will travel before stopping.
ReplyDeleteWith Newton's 2nd Law in mind, the distance the puck travels will depend mainly on the surface it's sliding across. Since hockey is played on ice, a relatively slippery surface, the puck will go quite a distance before friction brings it to a stop.
ReplyDeletethe above comments are very thoughtful and also true, one of the best ways to figure out how far the puck will travel would be to find its mass and the decide on the amount of force used to push it. once that is done you can find the acceleration and use that in an equation learned earlier in the year to find its distance.
ReplyDeleteThe reason the puck doesn’t keep a constant motion is all about friction and air resistance.
ReplyDeleteThe reason the puck doesn't slide forever is because of friction and the air resistance against the ice. Newton's Second Law states that force= mass X acceleration and because of this, force slowly declines causing acceleration to decline.
ReplyDeleteThe hockey puck will slide for a while and then stop because Newton's first law does not mention friction. Friction is the force that slows the puck down because the puck is rubbing the surface of the ice as it slides creating a force that works to slow it down because the particles are rubbing together, known as friction. You can use Newton's 2nd law to predict the distance the puck will travel by using a series of formulas. First you'd use the formula F=ma. You would find the mass of the puck and calculate the force in Newtons. Once you have found those two values you'd use them to find acceleration simply by dividing the force by the mass. Once you have all of these values you'd plug them into the distance formula you use from the big d equation if d(initial) and v(initial) are zero, which they are. Calculate the time, using a stop watch and then plug the values of time and acceleration in to find d.
ReplyDeleteFor the question for the previous week, the two objects tied together would fall faster because they are heavier than any one of those objects by themselves. This presents a paradox because if the 2 objects are together the heavier one should break free and end up fallling first and plumeting to the ground faster than the lighter object, not hit the ground at the same time as the marble. The person who contributed and discovered that in the absence of air resistance all free falling objects had the same acceleration was Gaileo Galilei.
The puck stopping does not violate Newton’s First Law because the law states that an object in motion will stay in motion with a constant speed. However that is only true if there is no friction or air resistance. Since an ice rink has both of these two things the puck will eventually have to come to a stop, not to mention that sooner or later it would hit a wall anyway. Newton’s Second law, which states that force is equal to mass times acceleration can be used to find how far the puck will go. However you would first need to know a couple more details about it. For example the mass of the puck, and how much force was used to push it.
ReplyDeleteThe puck gradually slowes down due to the effects of gravity, which creates friction, and air resistance. The ice reduces friction by being so smooth, but as time goes on the puck will decelerate. As to the second law, the weight of the puck can be multiplied by the acceleration to discover the amount of force that is needed to slow the puck down.
ReplyDeleteThanks for the comments this week.
ReplyDelete