Normal force, weight, Kinetic friction, and air resistance are a few I think of the top of my head.
I hope this helps
It’s definitely D: seeing all the options available to you and giving one a try
Answer: T2 = 7.07s
Explanation: The period of a loaded spring of spring constant k and mass m is given by
T= 2π √m/k
With 2π constant and k, it can be seen with little algebra that
T² is proportional to mass m
Hence (T1)²/m1 = (T2) ²/m2
Where T1 = 5, T2 =?, let m1 = m hence m2 = 2m.
By substituting, we have that
5²/m = (T2) ²/2m
25 / m = (T2) ²/2m
25 × 2m = (T2) ² × m
25 × 2 = (T2) ²
50 = (T2) ²
T2 = √50
T2 = 7.07s
Hello!

Use the equation KE = 1/2mv² to solve for the kinetic energy of the man.
We are given the mass and velocity, so plug these values into the equation:
KE = 1/2(80)(3²)
KE = 1/2(720)
KE = 360 J