Answer:
807.88N/m
Explanation:
<em>The question has some missing details in it, nevertheless, based on the given data we want to find the spring constant K</em>
Step one
given data
Unstretched length = 33.5 cm
Final length of the spring = 42.0 cm
Δx= 42-33.5
Δx=8.5cm to m= 0.085m
mass m= 7kg
The force on the spring
F=mg
F= 7*9.81
F=68.67N
Step two:
From Hooke's law, we can make k subject of formula and find the spring constant k, we have
F=kΔx---------1
make k subject of the formula
k=F/Δx
k= 68.67/ 0.085
k=807.88N/m
Answer:
The number of bright fringes per unit width on the screen is,
Explanation:
If d is the separation between slits, D is the distance between the slit and the screen and is the wavelength of the light. Let x is the number of bright fringes per unit width on the screen is given by :
is the wavelength
n is the order
If n = 1,
So, the the number of bright fringes per unit width on the screen is . Hence, the correct option is (B).
Hooke's Law: F = - k x
Potential energy, PE = [1/2] k x^2 = [1/2] kx x = [kx][x/2] = -Fx/2
F = - 2*PE / x = - 2*0.0030J / 0.0047m = -1.28 N (the negative sigh indicates that the force is opposed to the displacement of the spring)
:
D: Sóng có thể truyền qua khoảng không của không gian,
với tốc độ ánh sáng.