<span>A lubricant such as oil, grease, graphite powder can reduce the friction between two surfaces. Or using metal balls to space them and reduce the contact surface area as used in ball bearings.</span>
Answer:
Explanation:
A ) Distance between two adjacent anti-node will be equal to distance between two adjacent nodes . So the required distance is 15 cm .
B ) wave-length, amplitude, and speed of the two traveling waves that form this pattern are as follows
wave length = same as wave length of wave pattern formed. so it is 30 cm
amplitude = 1/2 the amplitude of wave pattern formed so it is .850 / 2 = .425 cm
Speed = frequency x wavelength ( frequency = 1 / time period )
= 1 / .075) x 30 cm
400 cm / m
C ) maximum speed
= ω A
= (2π / T) x A
= 2 X 3.14 x .85 / .075 cm / s
= 71.17 cm / s
minimum speed is zero.
D ) The shortest distance along the string between a node and an antinode
= Wavelength / 4
= 30 / 4
= 7.5 cm
Answer:
1. The image of the person is 1.41 m, virtual and formed at the back of the surface of the globe.
2. The person's image is 3.38 m tall.
Explanation:
From the given question, object distance, u = 0.75 m, object height = 1.8 m, radius of curvature of the reflecting globe, r = 8 cm = 0.08 m.
f =
=
= 0.04 m
1. The image distance, v, can be determined by applying mirror formula:
=
+ 
=
+ 
-
= 
= 
= - 
⇒ v = -
= - 1.41 m
The image of the person is 1.41 m, virtual and formed at the back of the surface of the globe.
2.
= 
= 
v = 
= 3.384
v = 3.38 m
The person's image is 3.38 m tall.
Answer:
73N
Explanation:Just multiply 1.2^2 by 50
To solve this problem we will use the concepts related to gravitational acceleration and centripetal acceleration. The equality between these two forces that maintains the balance will allow to determine how the rigid body is consistent with a spherically symmetric mass distribution of constant density. Let's start with the gravitational acceleration of the Star, which is

Here



Mass inside the orbit in terms of Volume and Density is

Where,
V = Volume
Density
Now considering the volume of the star as a Sphere we have

Replacing at the previous equation we have,

Now replacing the mass at the gravitational acceleration formula we have that


For a rotating star, the centripetal acceleration is caused by this gravitational acceleration. So centripetal acceleration of the star is

At the same time the general expression for the centripetal acceleration is

Where
is the orbital velocity
Using this expression in the left hand side of the equation we have that



Considering the constant values we have that


As the orbital velocity is proportional to the orbital radius, it shows the rigid body rotation of stars near the galactic center.
So the rigid-body rotation near the galactic center is consistent with a spherically symmetric mass distribution of constant density