Answer:
a) 
b) 
c) Compressing is easier
Explanation:
Given:
Expression of force:

where:



when the spring is stretched
when the spring is compressed
hence,

a)
From the work energy equivalence the work done is equal to the spring potential energy:
here the spring is stretched so, 
Now,
The spring constant at this instant:



Now work done:



b)
When compressing the spring by 0.05 m
we have, 
<u>The spring constant at this instant:</u>



Now work done:



c)
Since the work done in case of stretching the spring is greater in magnitude than the work done in compressing the spring through the same deflection. So, the compression of the spring is easier than its stretching.
The answer for this problem is clarified through this, the
system is absorbing (+). And now see that it uses that the SURROUNDINGS are
doing 84 KJ of work. Any time a system is overshadowing work done on it by the
surroundings the sign will be +. So it's just 12.4 KJ + 4.2 = 16.6 KJ.
Answer:
13.9
Explanation:
Apparent weight is the normal force. Sum of the forces on the alloy when it is submerged:
∑F = ma
N + B − W = 0
N + ρVg − mg = 0
6.6 + (0.78 × 1000) V (9.8) − (0.750) (9.8) = 0
V = 9.81×10⁻⁵
If x is the volume of the first material, and y is the volume of the second material, then:
x + y = 9.81×10⁻⁵
(7.87×1000) x + (4.50×1000) y = 0.750
Two equations, two variables. Solve with substitution:
7870 (9.81×10⁻⁵ − y) + 4500 y = 0.750
0.772 − 7870 y + 4500 y = 0.750
0.0222 = 3370 y
y = 6.58×10⁻⁶
x = 9.15×10⁻⁵
The ratio of the volumes is:
x/y = 13.9
Because weight W = M g, the ratio of weights equals the ratio of masses.
(M_m g)/ (M_w g) = [ (p^2 Man )/ (2 K_man)] / [ (p^2 Woman )/ (2 K_woman)
but p's are equal, so
K_m/K_m = (M_w g)/(M_m g) = W_woman / W_man = 450/680 = 0.662
Answer:
B. QC > 0; QH < 0
Explanation:
Given that there are two reservoir of energy.
Sign convention for heat and work :
1.If the heat is adding to the system then it is taken as positive and if heat is going out from the system then it is taken as negative.
2. If the work is done on the system then it is taken as negative and if the work is done by the system then it is taken as positive.
From hot reservoir heat is going out that is why it is taken as negative

From cold reservoir heat is coming inside the reservoir that is why it is taken as positive

That is why the answer will be
,