Answer:
v = 0.667 m / s, m = 6746 kg
Explanation:
For this exercise we must use the relationship between work and kinetic energy
W = ΔK
the work is defined by
W = F. x
bold indicates vectors
W = F x cos θ
in this case the force is in the same direction of displacement
W = F x
F x = K_f - K₀
as the body starts from rest the initial kinetic energy is zero
F x = ½ m v²
Now let's use the relationship between momentum and momentum
I = Δp
I = F t
Δp = m v_f - m v₀
as part of rest v₀ = 0
F t = m v
Let's write our system of equations
F x = ½ m v²
F t = m v
we have a system of two equations with two unknowns, let's divide the two expressions
x / t = ½ v
v = 2x / t
v = 2 10/30
v = 0.667 m / s
we look for the mass
F t = m v
m = F t / v
m = 150 30 / 0.667
m = 6746 kg
Answer:
1.24 J
Explanation:
The work done by a force is given by
where
F is the magnitude of the force
d is the displacement
is the angle between the directions of F and d
In this problem,
F = 0.18 N is the average force exerted by the muscles
d = 6.9 m is the displacement
(we assume the direction of the force is parallel to the displacement)
Substituting,
Answer:
Remember: in physics and music, frequency equates to pitch, and amplitude equates to loudness. Also, remember frequency is inversely proportional to wavelength- remember this!
Thus, (B) should be the correct answer, because, think about it, if a note is higher, than the wavelength should be shorter so the length should also be shorter, but in the case of B, if the cable is longer or thicker then the wavelength gets longer. Therefore, going from low to high, the string should be getting shorter, due to the fact that as wavelength gets shorter, frequency gets higher.
The velocity of an object determines if it is moving. If the velocity is zero, it is not moving. If it has a positive velocity, then it is moving forward. If it has a negative velocity, then it is moving backwards.
We can solve for the acceleration by using a kinematic equation. First we should identify what we know so we can choose the correct equation.
We are given an original velocity of 24 m/s, a final velocity of 0 m/s, and a time of 6 s. We and looking for acceleration (a) in m/s^2.
The following equation has everything we need:
So plug in the known values and solve for a:
0 = 24 + 6a
-24 = 6a
a = -4 m/s^2