Explanation:
the correct answer is the last one
Answer:
The speed is maximum and the acceleration is zero
Explanation:
- The speed of the mass in simple harmonic motion can be found by using the law of conservation of energy. In fact, the total mechanical energy of the mass-spring system is sum of kinetic energy and elastic potential energy:
where
m is the mass
v is the speed
k is the spring constant
x is the displacement
As we can see, when the displacement is zero (x=0), the term representing the kinetic energy is maximum, so v (the speed) is also maximum.
- The acceleration of the mass in simple harmonic motion is proportional to the restoring force acting on the mass, which is given by Hook's law
where
k is the spring constant
x is the displacement
When x = 0, F = 0, so the net force acting on the mass is zero. Therefore, this also means that the acceleration of the mass is also zero: a = 0.
Answer:
Theory
Explanation:
Conservation of energy is explained as a scientific law and not a theory because it does not explain why energy is conserved.
A law is a the statement of a scientific fact. It is a product of repeated experiment and observation through time. Most laws do not explain the reason for the logic behind their premise.
A theory on the other hand provides an explanation for an observed phenomenon. Most theories are no immutable. They are often changed when new finds are reported or made.
Laws are immutable and they stand still.
Answer:
When the bat hits the ball, it exerts some force on the ball. Just think about a home run hitter hitting a stationary ball. How far do you think it will go? Will it go more than 400 ft.? Probably not. While the kinetic energy transferred from the bat to the ball accounts for some energy of the ball, it does not account for all. Where is the mysterious energy coming from?
The answer is conservation of momentum. I just said momentum is conserved but how do I know that? I know that because of Newton's 2nd law: F=ma (Force equals mass times acceleration)
Conservation of momentum means that the harder you throw you, the harder the ball will bounce back at you. That is the reason it is easier to hit a home run on a fast ball than a curveball.
Conservation of momentum also means that the bat can transfer some of its momentum to the ball. This is why it is better to use a heavier bat if you swing just as fast. The momentum is the product of the mass and velocity, so to make it easier to understand;
a heavier bat swung at the same speed as a lighter bat will have more momentum.
