Answer:
Explanation:
The form of Newton's 2nd Law that we use for this is:
F - f = ma where F is the Force pulling the mass down the ramp forward, f is the friction trying to keep it from moving forward, m is the mass and a is the acceleration (and our unknown).
We know mass and we can find f, but we don't have F. But we can solve for that by rewriting our main equation to reflect F:
That's everything we need.
w is weight: 6.0(9.8). Filling in:
6.0(9.8)sin20 - .15(6.0)(9.8) = 6.0a and
2.0 × 10¹ - 8.8 = 6.0a and
11 = 6.0a so
a = 1.8 m/s/s
Answer:
a) L = 3.29 10⁻⁴ H, b)U = 5.33 10⁻² J
Explanation:
a) The inductance is a solenoid this given carrier
L =
The magnetic field inside the solenoid is
B = μ₀
hence the magnetic flux
Ф_B = B. A = μ₀
we substitute in the expression of inductance
L = N² μ₀ A /l
let's find the area of each turn
A = π r²
A = π 0.02²
A = 1.2566 10⁻³ m²
let's calculate
L = 250² 4π 10⁻⁷ 1.2566 10⁻² / 0.3
L = 3.29 10⁻⁴ H
b) The stored energy is
U = ½ L i²
let's calculate
U = ½ 3.29 10⁻⁴ 18²
U = 5.33 10⁻² J
Answer:
1. The best definition of refraction is ____.
a. passing through a boundary
b. bouncing off a boundary
c. changing speed at a boundary
d. changing direction when crossing a boundary
Answer: D
Bouncing off a boundary (choice b) is reflection. Refraction involves passing through a boundary (choice a) and changing speed (choice c); however, a light ray can exhibit both of these behaviors without undergoing refraction (for instance, if it approaches the boundary along the normal). Refraction of light must involve a change in direction; the path must be altered at the boundary.
Answer:
The duration of the movie is longer than 2 hrs.
Explanation:
Given:
The duration of the movie observed by the crew on the spacecraft is 2 hrs.
According to time-dilation formula:

Here,
is the required time,
is the original time,
is the velocity of the spacecraft and
is the velocity of light.
Since
, so
.
So the time required will be large.
Answer:
w = 3.2 rev / min
Explanation:
For this exercise we will use the centrine acceleration equal to the acceleration of gravity
a = v² / r
Angular and linear variables are related.
v = w r
Let's replace
a = w² r = g
w = √ g / r
r = d / 2
r = 175/2 = 87.5 m
w = √( 9.8 / 87.5)
w = 0.3347 rad / s
Let's reduce to rotations per min
w = 0.3347 rad / s (1 rov / 2pi rad) (60 s / 1 min)
w = 3.2 rev / min
Suppose the space station rotates counterclockwise, we have two possibilities for the car
The first car turns counterclockwise (same direction of the station
=
r
[texwv_{c}[/tex] =
/ r
[texwv_{c}[/tex] = 25.0 / 87.5
[texwv_{c}[/tex] = 0.286 rad / s
When the two rotate in the same direction their angular speeds are subtracted
w total = w -[texwv_{c}[/tex]
w total = 0.3347 - 0.286
w total= 0.487 rad / s
The car goes in the opposite direction of the station the speeds add up
w = 0.3347 + 0.286
w = 0.62 rad / s
From this values we can see that the person feels a variation of the acceleration of gravity, feels that he has less weight when he goes in the same direction of the season and that his weight increases when he goes in the opposite direction to the season.