Physical change is changing physically it eg appearance while chemical change is the molecular bonds water is always defined as H2O and not change chemically. Hope this answers your question.
Complete question:
A taut rope has a mass of 0.123 kg and a length of 3.54 m. What average power must be supplied to the rope to generate sinusoidal waves that have amplitude 0.200 m and wavelength 0.600 m if the waves are to travel at 28.0 m/s ?
Answer:
The average power supplied to the rope to generate sinusoidal waves is 1676.159 watts.
Explanation:
Velocity = Frequency X wavelength
V = Fλ ⇒ F = V/λ
F = 28/0.6 = 46.67 Hz
Angular frequency (ω) = 2πF = 2π (46.67) = 93.34π rad/s
Average power supplied to the rope will be calculated as follows
where;
ω is the angular frequency
A is the amplitude
V is the velocity
μ is mass per unit length = 0.123/3.54 = 0.0348 kg/m
= 1676.159 watts
The average power supplied to the rope to generate sinusoidal waves is 1676.159 watts.
High task repitition, forceful exertions, repetitive or sustained awkward posture
Answer: X = 52,314.12 N
Explanation: Let X be the force the feet of the athlete exerts on the floor.
According to newton's third law of motion the floor gives an upward reaction based on the weight of the athlete and the barbell which is known as the normal reaction ( based on the mass of the athlete and the barbell)
Mass of athlete = 87kg, mass of barbell = 600/ hence total normal reaction from the floor = 87* 61.22/ 9.8 *9.8 = 52,200N.
The athlete lifts the barbell from rest thus making it initial velocity u=0, distance covered = S = 0.65m and the time taken = 1.3s
The acceleration of the barbell is gotten by using the equation of constant acceleration motion
S= ut + 1/2at²
But u = 0
S = 1/2at²
0.65 = 1/2 *a (1.3)²
0.65 = 1.69 * a/2
0.65 * 2 = 1.69 * a
a = 0.65 * 2/ 1.69
a = 0.77m/s²
According to newton's second law of motion
Resultant force = mass * acceleration
And resultant force in this case is
X - 52,200 = (87 + 61.22) * 0.77
X - 52,200 = 148.22 * 0.77
X - 52, 200 = 114.132
X = 114.132 + 52,200
X = 52,314.12 N
