A hockey puck is set in motion across a frozen pond. if ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is?
2007-05-21 08:03:08 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Physics
Zero. With no friction and no air resistance, once that puck is in motion the only thing that'll stop it is the other side of the pond, unless someone hits it first.
2007-05-21 08:13:11 · answer #1 · answered by Navigator 7 · 0⤊ 0⤋
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it (Newton). Therefore, since the puck is in motion and you have eliminated the only forces acting on the puck, you would not need any force to keep the puck in motion (at least not until it ran out of pond and hit the shore).
The real question is when will the fights break out between the players?
2007-05-21 08:17:17 · answer #2 · answered by remowlms 7 · 1⤊ 0⤋
Zero force. Surprising, but true. This bizarre result stems from Newton's laws of motion.
Law 1: It takes a net force f > 0 to change velocity (dv/dt) of a mass m. This is called the law of inertia.
Law 2: f = dp/dt = d(mv)/dt = mdv/dt = ma; where p is called momentum. Since, by your question v = constant, dv/dt = 0, there is no change in velocity...no acceleration or deceleration. Thus, f = mdv/dt = m0 = ma = 0; so that there is no net force since the acceleration is 0.
Law 3: When f = 0, there is an equal, but opposite force for all forces that make up the net force. Thus, as your puck is traveling at a constant velocity (friction or not) there is no net force on it. QED zero as specified at the top.
2007-05-21 08:20:18 · answer #3 · answered by oldprof 7 · 1⤊ 0⤋
If you consider that there is no friction on the ice, then no force is necessary to keep the velocity constant.
If there is friction, then you need to provide a force that matches the force due to friction. That way, you cancel the friction: the sum of the forces becomes zero, and there is no acceleration (or deceleration) of the puck, ie its velocity remains constant.
2007-05-21 08:12:26 · answer #4 · answered by Damien 4 · 1⤊ 0⤋
If there is no friction of any kind, then the required force is zero.
2007-05-21 08:59:26 · answer #5 · answered by Superconductive Magnet 4 · 0⤊ 0⤋
through fact there is not any friction or air resistance, any rigidity will advance up the object to a persevering with speed. rigidity * time = mass * boost of speed boost of speed = (rigidity * time) / mass If preliminary speed = 0 m/s consistent speed = (rigidity * time) / mass rigidity = consistent speed * mass / time
2016-10-31 00:35:01 · answer #6 · answered by Anonymous · 0⤊ 0⤋
Force required is normal reaction,
N = -mg
2007-05-21 08:14:19 · answer #7 · answered by Alexander 6 · 0⤊ 2⤋
Nothing?
2007-05-21 08:11:28 · answer #8 · answered by somathus 7 · 0⤊ 1⤋