Answer:
A) 3.13 m/s
B) 5.34 N
C) W = 26.9 J
Explanation:
We are told that the position as a function of time is given by;
x(t) = αt² + βt³
Where;
α = 0.210 m/s² and β = 2.04×10^(−2) m/s³ = 0.0204 m/s³
Thus;
x(t) = 0.21t² + 0.0204t³
A) Velocity is gotten from the derivative of the displacement.
Thus;
v(t) = x'(t) = 2(0.21t) + 3(0.0204t²)
v(t) = 0.42t + 0.0612t²
v(4.5) = 0.42(4.5) + 0.0612(4.5)²
v(4.5) = 3.1293 m/s ≈ 3.13 m/s
B) acceleration is gotten from the derivative of the velocity
a(t) = v'(t) = 0.42 + 2(0.0612t)
a(4.5) = 0.42 + 2(0.0612 × 4.5)
a(4.5) = 0.9708 m/s²
Force = ma = 5.5 × 0.9708
F = 5.3394 N ≈ 5.34 N
C) Since no friction, work done is kinetic energy.
Thus;
W = ½mv²
W = ½ × 5.5 × 3.1293²
W = 26.9 J
Ye sit does. But since people weren’t there to hear it, doesn’t mean that it didn’t make a sound.
Answer:
450.78Hz
Explanation:
The frequency of wave in string is directly proportional to its tension. This is mathematically expressed as
F∝T
F = kT where k is the constant of proportionality
From the formula, k = F/T
F1/T1 = F2/T2 = k
If each violin is perfectly tuned at 440 Hz and under 245 N of tension then F1 = 440Hz, T1 = 245N
To get the frequency if the string A is tighten to 251N of tension,
T2 = 251N, F2 =?
Substituting the given values into the equation above to get F2 we have;
440/245 = F2/251
Cross multiplying
245F2 = 440×251
245F2 = 110,440
F2 = 110,440/245
F2 = 450.78Hz
Answer:
v
f=90km/h=25m/s
v_{_{i}}=0v
i=0
t=10\;\mathrm{s}t=10s
m=1000\;\mathrm{kg}m=1000kg
Explanation:
A ball is thrown straight upward and falls back to Earth. It means that it is coming to the initial position. Displacement is given by the difference of final position and initial position. The displacement of the ball will be 0. As a result velocity will be 0.
Acceleration is equal to the rate of change of velocity. So, its acceleration is also equal to 0.
Hence, displacement, velocity and acceleration are zero.