Answer:
Explanation:
The bead is moving on a vertical circular path so it must have a centripetal force towards the centre.
This force is equal to m v² / r
v is velocity of bead and r is radius of the circular path.
The vertical hoop is also rotating about a vertical axis passing through the centre at frequency f so the bead will experience a cetrifugal force due to rotation of the hoop. Its value is
m ω² r . Only at the point o degree and 180 degree , these forces are opposite to each other so at these points , the bead will be in equilibrium .
mv² / r = m ω² r
v² = ω² r²
v = ω r
= 2π f r
= 2 x 3.14 x 2 x 0.22
v = 2.76 m /s
For the bead to rise upto point θ = 90 degree , height achieved is radius R
required velocity = √ 2gR
= √ 2x 9.8x.22
= 2.076 m/s
This velocity is less than the velocity calculated earlier so the bead will be able to ride the required height.
v = 2.76 m/s
Answer:
72.98 km
Explanation:
Her displacement is simply the distance from her final position to her initial position.
Now, I've drawn and attached a triangle diagram to depict this her movement.
Point O is her initial starting point.
Point A is the first point she gets to after travelling north while point B is the final point after travelling north east.
From the triangle, the displacement will be the distance OB which is denoted by x and can be solved from cosine rule.
Thus;
x² = 62² + 26² - 2(62 × 26)cos 120
x² = 4520 + 806
x² = 5326
x = √5326
x = 72.98 km
Answer: the refraction of light by the atmosphere
Explanation: Refraction is the phenomenon in which there is a change in direction of light passing from one medium to another or from a gradual change in the medium.
Here in case of sunset, the sun rays passes through the varying density of atmosphere because of varying concentrations of dust particles.
Reflection is the phenomenon in which the light bounces back after falling on a surface.
Absorption is the phenomenon in which matter captures the electromagnetic radiations and thus the energy of photons is converted to internal energy of the system.
Having different densities being swirled rapidly will cause sedimentation. Sedimentation is the segmentation of the mixture creating layers of particles of these different densities. The process of rapid swirling is called differential centrifugation. An example use of this method is separation human blood into, red, platelet and white blood cells.
