Force equals mass time acceleration. Weight is a force and it can replace force in the equation. The acceleration would be gravity, which is an acceleration.
1.)
Fw (weight) = m (mass) · g (gravity, 9.8 m/s²)
Fw = m * 9.81 m/s²
560N = m · 9.81 m/s²
m ≈ 57.08 kg
2.)
d = 350 meters
t = 65 seconds
velocity = d/t
velocity = 350 meters / 65 seconds
velocity ≈ 5.38 meters/sec
3.)
Force = 35N
Distance = 2 meters
Work = Force · Distance
Work = 35N · 2 meters
Work = 70 J
Solution :
Given :
Mass attached to the spring = 4 kg
Mass dropped = 6 kg
Force constant = 100 N/m
Initial amplitude = 2 m
Therefore,
a). 

= 10 m/s
Final velocity, v at equilibrium position, v = 5 m/s
Now, 
A' = amplitude = 1.4142 m
b). 
m' = 2m
Hence, 
c). 

Therefore, factor 
Thus, the energy will change half times as the result of the collision.
Failed experiments, uncontrolled variables, invalid data, and generalized human error