axmls said:One of them relates an object's acceleration to the force applied on it, another gives the kinetic energy of a moving object, and the third is the momentum of a moving object.
beginner952 said:Thank you. I understand that much. What I don't understand is how they are used. For instance; I am a baseball fan and I am interested in the basic physics of bat and/or ball movements and force. If a ball is moving at 90mph and weighs 5 ounces it has 20250 of Kinetic energy. It has 450 of momentum. How are these used to determine Force? If at all. And where does the "a" in F= ma come from?
You cannot. And, in the usual case, the force is irrelevant. What you care about is the coefficient of restitution.beginner952 said:What I'm asking is how do I determine the force that will be applied to a stationary ball sitting on a tee, if the bat has 20250 of Ke and 450 of momentum?
OK. How do I calculate that? And, on the show Sports Science, and in books I've read, they talk about the ball hitting a wall with "x" amount of force. What are they talking about, and how did they determine that?jbriggs444 said:You cannot. And, in the usual case, the force is irrelevant. What you care about is the coefficient of restitution.
Sports Science is a joke. Force is not the almighty be all and end all of measurements that it is made out to be in such shows. It takes no particular strength and skill to generate multiple tons of force with a hammer and an anvil -- though the resulting force will be brief.beginner952 said:OK. How do I calculate that? And, on the show Sports Science, and in books I've read, they talk about the ball hitting a wall with "x" amount of force. What are they talking about, and how did they determine that?
Ok, thank you, I'm learning. So, when does F = ma apply? And how is "a" determined? If the ball is traveling at a constant rate of 90mph is "a" = 90? I'm having difficulty understanding F = ma.jbriggs444 said:Sports Science is a joke. Force is not the almighty be all and end all of measurements that it is made out to be in such shows.
The coefficient of restitution is determined by experiment. You bounce a ball off a golf club head at right angles and see what fraction of the initial energy is present after the rebound. This will usually be reasonably constant over a range of collisions. Given the impact velocity, head mass, impact angle and the coefficient of restitution, you can compute how the ball will move after the collision. You never have to know the force of impact.
beginner952 said:Ok, thank you, I'm learning. So, when does F = ma apply? And how is "a" determined? If the ball is traveling at a constant rate of 90mph is "a" = 90? I'm having difficulty understanding F = ma.
I'm confused. The kinetic energy in the moving bat applies a force to the ball, which makes the ball accelerate. But, my question is; how much force is the bat applying to the ball? How does one calculate how much force is needed to make a given mass accelerate, or gain momentum? If the ball weighs 5 ounces how much force is needed to make it move? 5 times "a" = F. I don't know what "a" is, so how do I get F?axmls said:The a is the acceleration of the ball for the duration that the force is applied. That is, if you hit a ball with a bat, while the bat is pushing the ball, a force is applied, and while the force is applied, the ball accelerates. The ball stops accelerating when the force is no longer applied. An acceleration is a change in velocity, so the force increases the velocity of the ball (accelerates it), and when the ball flies off the bat, it does so at a constant velocity, since the force is no longer acting on it.
You also need to know that acceleration ≠ velocity. Acceleration is the change in velocity per unit amount of time.beginner952 said:I'm confused. The kinetic energy in the moving bat applies a force to the ball, which makes the ball accelerate. But, my question is; how much force is the bat applying to the ball? How does one calculate how much force is needed to make a given mass accelerate, or gain momentum? If the ball weighs 5 ounces how much force is needed to make it move? 5 times "a" = F. I don't know what "a" is, so how do I get F?
"a" acceleration -- the rate of change of velocity over time. If you have a change in velocity that occurs over a brief time interval then the acceleration will be correspondingly large. The shorter the interval, the larger the acceleration. Accordingly, the shorter the interval the larger the force.beginner952 said:I'm confused. The kinetic energy in the moving bat applies a force to the ball, which makes the ball accelerate. But, my question is; how much force is the bat applying to the ball? How does one calculate how much force is needed to make a given mass accelerate, or gain momentum? If the ball weighs 5 ounces how much force is needed to make it move? 5 times "a" = F. I don't know what "a" is, so how do I get F?
The formulas F=ma, Ke=1/2mv2, and p=mv are fundamental equations in physics that help us understand the motion of objects. They describe the relationship between an object's mass, acceleration, velocity, and momentum, which are all crucial factors in understanding how objects move.
F=ma, Ke=1/2mv2, and p=mv are directly related to Newton's Laws of Motion. The first law states that an object will remain at rest or in uniform motion unless acted upon by an external force, which is represented by F=ma. The second law states that the force applied to an object is proportional to its mass and acceleration, which is represented by F=ma. The third law states that for every action, there is an equal and opposite reaction, which is reflected in the momentum equation, p=mv.
F=ma, Ke=1/2mv2, and p=mv are used to solve a variety of real-world problems in physics, engineering, and other scientific fields. For example, they can be used to calculate the force needed to accelerate a rocket into space, the kinetic energy of a car moving at a certain velocity, or the momentum of a baseball thrown by a pitcher.
The units of measurement used in these formulas are consistent with the International System of Units (SI). Force (F) is measured in newtons (N), mass (m) is measured in kilograms (kg), acceleration (a) is measured in meters per second squared (m/s^2), kinetic energy (Ke) is measured in joules (J), velocity (v) is measured in meters per second (m/s), and momentum (p) is measured in kilogram meters per second (kg*m/s).
While F=ma, Ke=1/2mv2, and p=mv are fundamental equations in physics, they have their limitations. These formulas assume that the motion of an object is in a straight line with a constant acceleration, and they do not take into account other factors such as air resistance or friction. They are also limited to objects moving at relatively low speeds compared to the speed of light.