Answer:
0 Joules
Explanation:
The work done is given by

where,
F = Force applied
s = Displacement of the object = 0 m
= Angle between the force applied and the horizontal = 0

Work is only observed when there is a displacement.
The work done by me is 0 Joules as I was unable to move it.
Answer:
3.95 m
Explanation:
m = 1 kg, h = 100 m, k = 125 N/m
Let the spring is compressed by y.
Use the conservation of energy
potential energy of the mass is equal to the energy stored in the spring
m x g x h = 1/2 x ky^2
1 x 9.8 x 100 = 0.5 x 125 x y^2
y^2 = 15.68
y = 3.95 m
Answer:
2.47 m/s
Explanation:
Momentum = Mass X Velocity
If they were locked together, it means its a perfectly inelastic collision. Therefore,
Total momentum before = Total momentum after
Total momentum before = (20 X 20) - (18 X 17)
= 94
Total momentum after = 94
Y = Object speed after collision
94 = (20+18)Y
Y = 2.47368421 m/s
A perfect black body can’t be realized
Are you referring to the fact that water is a compound while hydrogen is an element? If I'm wrong just comment and clarify and I can edit it, I don't even know what kind of unit you're in. :)