Answer:
c. above the point of unit elasticity.
Explanation:
The elastic portion of the downward-sloping straight-line demand curve lies above the point of unit elasticity. Supply and demand are fundamental concept in economics. The demand curve shows how much of a good people will want at a different prices. The demands curves illustrates the intuition why people purchase a good for a lower price. For the demand curve, the price is always shown on the vertical axis and the demand curve is shown on the horizontal axis. Thus , the quantity demanded increases as the price gets lower. However, the price elasticity of the demand curve varies along the demand curve. This is because there is a key distinction between the gradient and the elasticity. The gradient which is the slope of the line is always the same in the demand curve but elasticity of the demand changes in the percentage of the quantity demand. Therefore, elasticity will vary along the downward-sloping straight - line demand curve. So, in a downward-sloping straight-line demand curve, the elastic portion is usually above the point of unit elasticity
Answer:
(a) 0.942 m
(b) 18.84 m/s
(c) 2366.3 m/s²
(d) 0.05 s
Explanation:
(a) In one revolution, it travels through one circumference, 2πr = 2 × 3.14 × 0.15 m = 0.942 m.
(b) Its frequency, f, is 1200 rev/min =
rev/s = 20 rev/s.
Its angular frequency, ω = 2πf = 2π × 20 = 40π
The speed is given by
v = ωr = 40π × 0.15 = 6π = 18.84 m/s
(c) Its acceleration is given by, a = ω²r = (40π)² × 0.15 = 2366.3 m/s²
(d) The period is the inverse of the frequency because it is the time taken to complete one revolution.

T = 1/20 = 0.05 s
Answer:
x₂=0.44m
Explanation:
First, we calculate the length the spring is stretch when the first block is hung from it:

Now, since the stretched spring is in equilibrium, we have that the spring restoring force must be equal to the weight of the block:

Solving for the spring constant k, we get:

Next, we use the same relationship, but for the second block, to find the value of the stretched length:

Finally, we sum this to the unstretched length to obtain the length of the spring:

In words, the length of the spring when the second block is hung from it, is 0.44m.
Answer:
24.325 kg m/s
Explanation:
Initial momentum, pi = 18 kg m/s
F = < -4, 12, 0>
t = 0.5 s
Let the final momentum is pf.
The magnitude of force is

According to the Newton's second law, the rate of change of momentum is equal to the force.


pf - 18 = 6.325
pf = 24.325 kg m/s
Thus, the momentum of body after 0.5 s is 24.325 kg m/s.