Answer:
Attracting means pulling toward you and repelling means pushing away
Explanation:
(a) The free body of all the forces include, frictional force, weight of the box acting perpendicular and another acting parallel to the plane.
(b) When the box is sliding down, the frictional force acts towards the right.
(c) When the box slides up, the direction of the frictional force changes, it acts towards the left.
<h3>
Free body diagram</h3>
The free body diagram of all the forces on the box is obtained by noting the upward force and downward forces on the box as shown below;
/ W2
Ф → Ff
↓W1
where;
- Ff is the frictional force resisting the down motion of the box
- W1 is the perpendicular component of the box weight = Wcos(33)
- W2 is the parallel component of the box weight = Wsin(33)
(b) When the box is sliding down, the frictional force acts towards the right.
(c) When the box slides up, the direction of the frictional force changes, it acts towards the left.
Learn more about free body diagram of inclined objects here: brainly.com/question/4176810
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<h2>QUESTION:- </h2>
➜what is kepler's law??
Kepler gave the three laws or theorems of motion of the orbitals bodies
This law state that the celestial bodies revolves around the stars in elliptical orbit and star as a single focus.
Example :- Earth revolves around the Sun as assuming it as single focus
This also shows that earth revolves around the sun in elliptical orbit.
Area covered by the planet is equal in equal duration of time irrespective of the position of the planet.
It also states that Angular momentum is constant
As Angular momentum is constant it means areal velocity is also constant.
where:-
A is the area.
T is the time.
L is the angular momentum.
M is the mass of the body.
square of the time of the revolution is directly proportional to the cube of the distance between the planet and star in Astronomical unit.
where:-
T = time of revolution
a is the distance between the planet and star.
Answer:
a) x = (0.0114 ± 0.0001) in
, b) the number of decks is 5
Explanation:
a) The thickness of the deck of cards (d) is measured and the thickness of a card (x) is calculated
x = d / 52
x = 0.590 / 52
x = 0.011346 in
Let's look for uncertainty
Δx = dx /dd Δd
Δx = 1/52 Δd
Δx = 1/52 0.005
Δx = 0.0001 in
The result of the calculation is
x = (0.0114 ± 0.0001) in
b) You want to reduce the error to Δx = 0.00002, the number of cards to be measured is
#_cards = n 52
The formula for thickness is
x = d / n 52
Uncertainty
Δx = 1 / n 52 Δd
n = 1/52 Δd / Δx
n = 1/52 0.005 / 0.00002
n = 4.8
Since the number of decks must be an integer the number of decks is 5