Answer:
Approximately
.
Explanation:
This question suggests that the rotation of this object slows down "uniformly". Therefore, the angular acceleration of this object should be constant and smaller than zero.
This question does not provide any information about the time required for the rotation of this object to come to a stop. In linear motions with a constant acceleration, there's an SUVAT equation that does not involve time:
,
where
is the final velocity of the moving object,
is the initial velocity of the moving object,
is the (linear) acceleration of the moving object, and
is the (linear) displacement of the object while its velocity changed from
to
.
The angular analogue of that equation will be:
, where
and
are the initial and final angular velocity of the rotating object,
is the angular acceleration of the moving object, and
is the angular displacement of the object while its angular velocity changed from
to
.
For this object:
, whereas
.
The question is asking for an angular acceleration with the unit
. However, the angular displacement from the question is described with the number of revolutions. Convert that to radians:
.
Rearrange the equation
and solve for
:
.
Answer: A) O N
Explanation:
An object in motion will maintain its state of motion. The presence of an unbalanced force changes the velocity of the object.
Answer:
4.2 km
Explanation:
A triangle is a polygon with three sides and three angles. There are different types of triangles such as isosceles triangle, scalene triangle, equilateral triangle and right angled triangle.
Sine rule states that for a triangle with angles A,B and C and corresponding opposite sides a, b, and c, the following formula holds:

Let the starting point be A, hence the side opposite to the angle = a = distance travelled in north east direction.
Let the point of 60° of northeast be B = 90° + (90° - 60°) = 120°, hence the side opposite to the angle = b = resultant displacement = 8 km.
Let C be the endpoint, hence the side opposite to the angle = c = distance travelled north = 5 km
Using sine rule:

∠A + ∠B + ∠C = 180° (sum of angle in a triangle)
∠A + 120 + 32.8 = 180
∠A = 27.2°

Therefore she travelled 4.2 km in the north east direction
Answer:
3.99*10^-3N/C
Explanation:
Using
Ep= kq/r²
Where r = 0.6mm = 0.6*10^-3m
K= 8.9*10^9 and q= 1.6*10^-19
So = 8.9*10^9 * 1.6*10^-19/0.6*10^-3)²
= 3.99*10^-3N/C
Answer:
★The second law of refraction
The ratio of sine of angle of incidence to the sine of angle of refraction is a constant for a light of given colour and for a given pair of media. This law is also called Snell's law of refraction. If 'i' is the angle of incidence and 'r' is the angle of refraction then, Sin i/Sin r = constant
This constant value is called the refractive index of the second medium with respect to the first.