Answer:
The kinetic energy of the mass at the instant it passes back through the equilibrium position is 0.06500 J.
Explanation:
Given that,
Mass = 2.15 kg
Distance = 0.0895 m
Amplitude = 0.0235 m
We need to calculate the spring constant
Using newton's second law

Where, f = restoring force


Put the value into the formula


We need to calculate the kinetic energy of the mass
Using formula of kinetic energy

Here, 

Here, 


Put the value into the formula


Hence, The kinetic energy of the mass at the instant it passes back through the equilibrium position is 0.06500 J.
A baseball would hit the bat harder. This is because the baseball is a lot heavier and more dense than the plastic ball. The keyword that you're looking for is density. The baseball is dense.
Answer:

Explanation:
= Cambio en la longitud de la cuerda = 0.25 cm
T = tensión en cuerda
A = Área de la cadena = 
d = Diámetro de la cuerda = 0.2 cm
L = Longitud original de la cuerda = 1.6 m
El cambio de longitud de una cuerda viene dado por

La tensión en la cuerda es
.