Answer:
The same amount of energy is required to either stretch or compress the spring.
Explanation:
The amount of energy required to stretch or compress a spring is equal to the elastic potential energy stored by the spring:

where
k is the spring constant
is the stretch/compression of the spring
In the first case, the spring is stretched from x=0 to x=d, so

and the amount of energy required is

In the second case, the spring is compressed from x=0 to x=-d, so

and the amount of energy required is

so we see that the amount of energy required is the same.
Answer:
Heat needed = 71.19 J
Explanation:
Here heat required can be calculated by the formula
H = mL
M is the mass of water and L is the latent heat of vaporization.
Mass of water, m = 31.5 g = 0.0315 kg
Latent heat of vaporization of water = 2260 kJ/kg
Substituting
H = mL = 0.0315 x 2260 = 71.19 kJ
Heat needed = 71.19 J
Required Heat = Q
Q = Mass * specific heat of water * change in temp.
Q = 5g * 1g/cal*degC * 20degC
Q = 100 cal of heat is required
To convert calories to Joules,
1 cal = 4.184 Joules
100cal = 418.4 J of heat is needed
Answer:
Part 1: 0.3789
Part 2: 746 J
Part 3: 2.162 kW
Explanation:
Part 1:
Eff= 
Eff= 0.378873 ≈ 0/3789
Part 2:
W= 0.3789(1969)
W= 746 J
Part 3:

Power= 2162.3188 Watts
2162.3188 W-----> 2.162 kW