Answer:
[tex]0.886[/tex] N buoyant force is exerted by air
Explanation:
My weight is [tex]75[/tex] Kg
Weight = mass * gravity
As we know
Buoyant Force is equal to the product of density * acceleration due to gravity and volume of the body
Assuming weight density is a bit less than that of water or equal to water i.e [tex]997.77[/tex] kg/m3
Volume is equal to mass / density
[tex]= 75[/tex] Kg * g/[tex]997.777[/tex]
[tex]= 0.0751[/tex] * g
Buoyant Force
= Volume * g * density
[tex]= 0.0751 * 9.8 * 1.2041[/tex]kg/m3
[tex]= 0.886[/tex] N
A wheel has an angular speed of 32 rev/s when it experiences a constant angular acceleration of 65 rev/s2 which causes it to spin FASTER. During this time the wheel completes 92 rev. Determine how long the wheel was experiencing this angular acceleration and how fast the wheel was spinning at the end of this period. Assume that the wheel doesn't change the direction of its spin.
Answer:
ωf = 113.95 rev/s
t = 1.26 s
Explanation:
We can use the third equation of motion to find out the final spinning speed of the wheel:
[tex]2\alpha \theta = \omega_f^2 -\omega_i^2\\[/tex]
where,
α = angular acceleration = 65 rev/s²
θ = No. of revolutions completed = 92 rev
ωf = final angular speed = ?
ωi = initial angular speed = 32 rev/s
Therefore,
[tex](2)(65\ rev/s^2)(92\ rev) = \omega_f^2 - (32\ rev/s)^2\\\omega_f^2 = 11960\ rev^2/s^2 + 1024\ rev^2/s^2\\\omega_f = \sqrt{12984\ rev^2/s^2}[/tex]
ωf = 113.95 rev/s
Now, for the time we can use the first equation of motion:
[tex]\omega_f = \omega_i +\alpha t\\113.95\ rev/s - 32\ rev/s = (65\ rev/s^2)t\\t = \frac{81.95\ rev/s}{65\ rev/s^2}\\\\[/tex]
t = 1.26 s
what happens during subduction
Answer:
Subduction , Latin for "carried under," is a term used for a specific type of plate interaction. It happens when one lithospheric plate meets another—that is, in convergent zones —and the denser plate sinks down into the mantle.
What is characteristic of a good insulator?
A. Electrons are usually not moving at all.
B. Electrons are free to move around.
C. Electrons are semi-free to move around.
D. Electrons are tightly bound to the nuclei.
Answer:
D. Electrons are tightly bound to the nuclei.
Explanation:
In an insulator, the electrons of the outer most shell are bound with a very high electrostatic forces coming from the nucleus of each atom so electrons cannot flow around all atoms making up the material as in a conductor.
The characteristic of a good insulator is Electrons are tightly bound to the nuclei. (option d)
In a good insulator, electrons are tightly bound to the nuclei of their atoms. This means that they are not free to move around within the material, unlike conductors where electrons are relatively loosely bound and can move freely. Due to this strong binding, electrons in insulating materials cannot carry an electric charge or energy easily from one atom to another.
When an electric field is applied to an insulator, the electrons may experience a small displacement within their respective atoms, but they generally do not move from one atom to another or flow through the material like they would in a conductor. As a result, insulators prevent the flow of electric current and are used to isolate or protect conductive elements from accidental contact.
So, the correct answer is D. Electrons are tightly bound to the nuclei.
To know more about insulator here
https://brainly.com/question/2619275
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Brian Lara is a cricketer playing in the field on the second day of a cricket test-match. He exerts a forward force on the 0.145kg cricket ball, as he catches it, to bring it to rest from a speed of 38.2m/s. During the process, his hand recoils a distance of 0.135m. Determine the acceleration of the ball and the force which is applied to it by Brian Lara.
Answer:
a = -3984.6 m/s²
F = 577.76 N
Explanation:
The acceleration of the ball can be calculated by using the third equation of motion:
[tex]2as = v_f^2 - v_i^2\\[/tex]
where,
a = acceleration of ball = ?
s = distance covered = recoil distance = 0.135 m
vf = final speed = 0 m/s
vi = initial speed = 38.2 m/s
Therefore,
[tex]2(0.135\ m)a = (0\ m/s)^2-(38.2\ m/s)^2\\[/tex]
a = -3984.6 m/s²
here negative sign shows deceleration.
Now, for the force applied by Brian Lara will be equal in magnitude but opposite in direction of the force required to stop the ball:
[tex]F = -ma\\F = -(0.145\ kg)(-3984.6\ m/s^2)\\[/tex]
F = 577.76 N
A 0.545-kg ball is hung vertically from a spring. The spring stretches by 3.56 cm from its natural length when the ball is hanging at equilibrium. A child comes along and pulls the ball down an additional 5cm, then lets go. How long (in seconds) will it take the ball to swing up and down exactly 4 times, making 4 complete oscillations before again hitting its lowest position
Answer:
t = 9.52 s
Explanation:
This is an oscillatory motion exercise, in which the angular velocity is
w = [tex]\sqrt{ \frac{k}{m} }[/tex]
Let's use hooke's law to find the spring constant, let's write the equilibrium equation
F_e - W = 0
F_e = W
k x = m g
k = [tex]\frac{m g}{x}[/tex]
k = 0.545 9.8 /0.0356
k = 150 N / m
now the angular velocity is related to the period
W = 2π / T
we substitute
4π² T² = k /m
T = 4pi² [tex]\sqrt{ \frac{m}{k} }[/tex]
we substitute
T = 4 pi² [tex]\sqrt{ \frac{0.545}{150} }[/tex]
T = 2.38 s
therefore for the spring to oscillate 4 complete periods the time is
t = 4 T
t = 4 2.38
t = 9.52 s
Is this right or they wrong definitions which ones are the right ones someone !!!!!
Answer:
They are right.
Explanation:
Answer:
Mechanical Energy : KE + PE
Conversion : "When energy transfers from one form to another"
Potential Energy: the energy possessed by a body by virtue of its position relative to others , stresses within itself, electric charge , and other factors .'
Kinetic Energy: energy of an object in motion
Law of conservation of energy: KE+PE+friction=KE
Explanation:
First of all mechanical energy is kinetic energy plus potential energy (it is the energy of movement) So:
Mechanical Energy : KE + PE
Conversion is when energy converts or becomes a different form. So:
Conversion : "When energy transfers from one form to another"
Potential energy is stored energy, in Physics I or AP Physics I, it is often due to it being at a height, but batteries, foods, etc. are also example of it, so:
Potential Energy: the energy possessed by a body by virtue of its position relative to others , stresses within itself, electric charge , and other factors .'
Kinetic energy is for objects in motion so you got it right!
Kinetic Energy: energy of an object in motion
The law of conservation of energy means there is the same amount of energy before, as there is after, so when you see an equation with energy on both sides, it is usually this. Also, this is the last question left, so this has to be the answer.
Law of conservation of energy: KE+PE+friction=KE
sound wave of a wave length of 0.56 meters if its speed is 280 m/s what is the wave frequency
Answer:
500 Hz
Explanation:
Formula for finding wave frequency is,
f = c/λ
f = frequency
c = speed (m/s)
λ = wave length (m)
f = c/λ
f = 280/0.56
f = 500
∴ wave frequency is 500 Hz
What happens when a neutral atom gains an electrons?
Answer:
The neutral atom becomes an anion.
Explanation:
When a neutral atom gains an electron (e−), the number of protons (p+) in the nucleus remains the same, resulting in the atom becoming an anion (an ion with a net negative charge).
Which of the following is NOT a natural
source of pollution?
A. erupting volcanoes
B. dust storms
C. construction
D. forest fires
Answer:
hi
Explanation:
answer is C
have a nice day
3.
Two Cars, A and B, (starting, at the same time, from the same point) are moving
with average speeds of 40 km/h and 50 km/h, respectively, in the same direction.
Find how far will Car B be from Car A after 3 hours.
Answer:
car B will be 30 Km ahead of car A.
Explanation:
We'll begin by calculating the distance travelled by each car. This is illustrated below:
For car A:
Speed = 40 km/h
Time = 3 hours
Distance =?
Speed = distance / time
40 = distance / 3
Cross multiply
Distance = 40 × 3
Distance = 120 Km
For car B:
Speed = 50 km/h
Time = 3 hours
Distance =?
Speed = distance / time
50 = distance / 3
Cross multiply
Distance = 50 × 3
Distance = 150 Km
Finally, we shall determine the distance between car B an car A. This can be obtained as follow:
Distance travelled by car B (D₆) = 150 Km
Distance travelled by car A (Dₐ) = 120 Km
Distance apart =?
Distance apart = D₆ – Dₐ
Distance apart = 150 – 120
Distance apart = 30 Km
Therefore, car B will be 30 Km ahead of car A.
