The illustration shows a device known as newtons cradle. The balls in a newtons cradle are all identical in mass and diameter. A group of students perform several experiments using this device they pulled varying numbers Oh balls from the left side of the newtons cradle and let them drop so that they would collide with the remaining balls at rest. In all cases one or more balls at rest move to the right following the collision. The table shows the data collected from these experiments .
Beginning number of balls set in motion at left :Ball 1/ 1 Ball 2/ 2 Ball 3/ 3 Ball 4/ 4 Ball 5/ 5
Final number of balls in motion at right after the collision: Ball 1/ 1 Ball 2/ 2 Ball 3/ 3 Ball 4/ 4 Ball 5/ 5
QA.Consider the newtons cradle as a system what is true about the initial momentum and final momentum as the newtons cradle in each trial. On what principle do you base your answers to this question?
QB.What relationship do you observed in the data, and what does this relationship indicate about this system?
QC. If a student pulled one ball from the left and one from the right and let both balls drop simultaneously, What do you predict would happen.
Answers
Answer:
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QUESTION:
Let's say you have three 20-foot putts. Same stimp meter (pace on the green). Let's say in all cases, the green is flat after the hole. I.e. don't worry about things like the ball running away or anything.
Putt 1 travels flat and then shortly before the hole, it rises 6 inches.
Putt 2 has an rise of 6 inches right after you hit it, and then travels flat to the hole the rest of the way.
Putt 3 rises 6 inches gently from the ball to the hole at a constant angle.
Do you hit all three putts the same initial speed? Follow up question : What if you have the same 20 foot putt but halfway to the hole the ground rises 8 inches, and then drops 2 inches and then flattens out the rest of the way to the hole. . .same speed?
ANSWER:
Refer to the figure. If there were no friction, it would make no difference how the rise occurred, only the amount of rise. In that case vhole=√(vputt2-2gh). However, there is friction which will slow the ball further and the frictional force on a slope (f=μmgcosθ) will be different than on level ground (f=μmg); here μ is the coefficient of friction (essentially, I believe, what is measured by the "stimp meter"), m is the mass of the ball, and g is the acceleration due to gravity. Since the frictional force is smaller on the slope, you might think that less energy is lost to friction on the slope. But, what matters is not the force but its product with the distance s over which it acts, specifically the work done by friction is Wf=-fs where the negative sign indicates that the friction takes energy away from the ball. When the ball is moving forward along along the segment L2, the distance it travels is s=L2/cosθ and so the work done is Wf=fs=(μmgcosθ)(L2/cosθ)=μmgL2, exactly the same as if the slope was not there. The total work done by friction, regardless of the path, is Wf=μmgL. The final velocity is then vhole=√[vputt2-2g(h+μL)].
QUESTION:
Hello I have been wondering why basketball shoes have tread. I get why shoes for outdoor activities do but wouldn't a basketball shoe work with no tread like race car tires.
ANSWER:
If the floor is always perfectly dry, there is no reason. However, because of players sweating there is always a chance of hitting a wet spot. Treads on a road tire channel water away to prevent hydroplaning and I assume that would be the case for shoe treads as well. Also, increasing surface area does not increase traction because the frictional force for dry friction depends only how hard the shoe is being pressed to the floor (your weight) and the coefficient of friction between wood and rubber. Dragsters have "bald" tires because they are made of a material designed to melt when the heat up, essentially gluing the tire to the road for super friction.
QUESTION:
I'm coordinating a piece of action for a tvc (tv ad), which requires me to build a rig to raise an actor 3 m off the ground, as if he is being taken away by aliens! It's been a long time since school for me, however I feel that there would be a formula that would assist me in calculating how much counterweight is required on a pulley system with 2:1 MA to raise an 80kg actor 3m in 1.5 seconds? Are you able to clarify the principals to be used in calculating this problem? This is definitely not homework!
♠ Answer:
Whether you know it as Newton's Cradle or the Executive Ball Clicker, chances are you've seen the educational desk toy that seems to defy explanation. The device consists of a row of five metal balls — positioned to just barely touch one another — suspended from a frame by thin wires.
When a ball on one end of the cradle is pulled away from the others and then released, it strikes the next ball in the cradle, which remains motionless. But the ball on the opposite end of the row is thrown into the air, then swings back to strike the other balls, starting the chain reaction again in reverse.
♠ Explanation:
The device can be explained with some of the fundamental principles of physics and mechanics (as theorized by Sir Isaac Newton, René Descartes and others). Newton's Cradle aptly demonstrates the principle of the conservation of momentum (mass times speed). This principle states that when two objects collide, the total momentum of the objects before the collision is equal to the total momentum of the objects after the collision.
In other words, when the first ball of Newton's Cradle collides with the second, the first ball stops, but its momentum isn't lost, just transferred to the second ball, then the third, then the fourth, until it reaches the very last ball. You witness this conservation of momentum as the last ball swings into the air with nearly the same momentum as the first ball. Thus, if two balls are lifted into the air on one end of the device and released, then two balls on the opposite end will swing in response.
This continuous clicking of balls is also proof of Newton's law of the conservation of energy, which states that energy can't be created or destroyed but that it can change forms. Newton's Cradle demonstrates this last part of the law quite well, as it converts the potential energy of one ball into kinetic energy that is transferred down the line of balls and ultimately results in the upward swinging of the last ball.