Answer:
The work done to get you safely away from the test is 2.47 X 10⁴ J.
Explanation:
Given;
length of the rope, L = 70 ft
mass per unit length of the rope, μ = 2 lb/ft
your mass, W = 120 lbs
mass of the 70 ft rope = 2 lb/ft x 70 ft
= 140 lbs.
Total mass to be pulled to the helicopter, M = 120 lbs + 140 lbs
= 260 lbs
The work done is calculated from work-energy theorem as follows;
W = Mgh
where;
g is acceleration due gravity = 32.17 ft/s²
h is height the total mass is raised = length of the rope = 70 ft
W = 260 Lb x 32.17 ft/s² x 70 ft
W = 585494 lb.ft²/s²
1 lb.ft²/s² = 0.0421 J
W = 585494 lb.ft²/s² = 2.47 X 10⁴ J.
Therefore, the work done to get you safely away from the test is 2.47 X 10⁴ J.
Given Information:
Wavelength = λ = 39.1 cm = 0.391 m
speed of sound = v = 344 m/s
linear density = μ = 0.660 g/m = 0.00066 kg/m
tension = T = 160 N
Required Information:
Length of the vibrating string = L = ?
Answer:
Length of the vibrating string = 0.28 m
Explanation:
The frequency of beautiful note is
f = v/λ
f = 344/0.391
f = 879.79 Hz
As we know, the speed of the wave is
v = √T/μ
v = √160/0.00066
v = 492.36 m/s
The wavelength of the string is
λ = v/f
λ = 492.36/879.79
λ = 0.5596 m
and finally the length of the vibrating string is
λ = 2L
L = λ/2
L = 0.5596/2
L = 0.28 m
Therefore, the vibrating section of the violin string is 0.28 m long.
<span>Newton's law of gravitation is attractive, whereas Coulomb's law is attractive or repulsive. Both are proportional to the inverse square of distance.</span>
Its acceleration is constant.
B. 1520 is the difference between their weights.
