PHYSICS COLLEGE

How long does it take a wheel that is rotating at 33.3 rpm to speed up to 78.0 rpm if it has an angular acceleration of 2.15 rad/ s 2?

Answers

Answer 1

Answer:

initial angular speed is given by 33.3 rpm

$w_0 = 2\pi (33.3)/(60)$

$w_0 = 3.49 rad/s$

final angular speed is given by 78 rpm

$w_f = 2\pi (78)/(60)$

$w_f = 8.17 rad/s$

now by using kinematics we will have

$w_f = w_0 + \alpha * t$

$8.17 = 3.49 + 2.15 * t$

$t = 2.17 seconds$

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Alex throws a 0.15-kg rubber ball down onto the floor. The ball’s speed just before impact is 6.5 m/s, and just after is 3.5 m/s. If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force applied by the floor on the ball?
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Bryan Allen pedaled a human-powered aircraft across the English Channel from the cliffs of Dover to Cap Gris-Nez on June 12, 1979.(a) He flew for 169 min at an average velocity of 3.53 m/s in a direction 45° south of east. What was his total displacement?

(b) Allen encountered a headwind averaging 2.00 m/s almost precisely in the opposite direction of his motion relative to the Earth. What was his average velocity relative to the air?

(c) What was his total displacement relative to the air mass?

Answers

Answer:

a) $s=35794.2\ m$

b) $v_w=3.53\ m.s^(-1)$

c) $s_w=56074.2\ m$

Explanation:

Given:

duration of flight, $t=169* 60=10140\ s$

velocity of flight, $v=3.53\ m.s^(-1)$

direction of flight, $45^(\circ)$ to the south of east

Now the total displacement:

$s=v.t$

$s=3.53* 10140$

$s=35794.2\ m$

Velocity of air, $v_a=2\ m.s^(-1)$

When the aircraft encounters a headwind in the opposite direction to the velocity of motion then the speed of the aircraft is lowered with respect to the ground.

But when the speed is observed with respect to the wind the reduced velocity of the aircraft is observed from an opposite moving wind having a magnitude equal to the difference in velocity of the aircraft. This results in no change in the apparent velocity of the aircraft.

Mathematically:

Velocity of the aircraft with respect to the ground:

$v_(g)=v-v_a$

$v_(g)=3.53-2$

$v_g=1.53\ m.s^(-1)$

Now the velocity of the aircraft with respect to the wind:

$v_w=v_g+v_a$

$v_w=1.53+2$

$v_w=3.53\ m.s^(-1)$

Now the total displacement with respect to the wind:

$s_w=v_w.t+v_a.t$

$s_w=3.53* 10140+2* 10140$

$s_w=56074.2\ m$

PLEASE HELP QUICKLY!A volleyball player jumps to hit a ball horizontally at 7.0 m/s straight on. If the
height at which the ball was hit is 3.0 m tall, how far did the ball go horizontally
before it hit the ground?
5.5 m
3.6 m
O 4.3 m
4.2 m

Answers

Answer:

5.5 is the correct answer

please keeps as Brainly list

Assuming the same initial conditions as described in FNT 2.2.1-1, use the energy-interaction model in two different ways (parts (a) and (b) below) to determine the speed of the ball when it is 4 meters above the floor headed down: a) Construct a particular model of the entire physical process, with the initial time when the ball leaves Christine’s hand, and the final time when the ball is 4 meters above the floor headed down.
b) Divide the overall process into two physical processes by constructing two energy-system diagrams and applying energy conservation for each, one diagram for the interval corresponding to the ball traveling from Christine’s hand to the maximum height, and then one diagram corresponding to the interval for the ball traveling from the maximum height to 4 meters above the floor headed down.
c) Did you get different answers (in parts (a) and (b)) for the speed of the ball when it is 4 meters above the floor headed down?

Answers

Answer:

(a). Vf = 7.14 m/s

(b). Vf = 7.14 m/s

(c). same answer

Explanation:

for question (a), we would be applying conservation of energy principle.

but the initial height is h = 1.5 m

and the initial upward velocity of the ball is Vi = 10 m/s

Therefore

(a). using conservation law

Ef = Ei

where Ef = 1/2mVf² + mghf ........................(1)

also Ei = 1/2mVi² + mghi ........................(2)

equating both we have

1/2mVf² + mghf = 1/2mVi² + mghi

eliminating same terms gives,

Vf = √(Vi² + 2g (hi -hf))

Vf = √(10² + -2*9.8*2.5) = 7.14 m/s

Vf = 7.14 m/s

(b). Same process as done in previous;

Ef = Ei

but here the Ef = mghf ...........(3)

and Ei = 1/2mVi² + mghi ...........(4)

solving for the final height (hf) we relate both equation 3 and 4 to give

mghf = 1/2mVi² + mghi ..............(5)

canceling out same terms

hf = hi + Vi²/2g

hf = 1.5 + 10²/2*9.8 = 6.60204m ............(6)

recalling conservation energy,

Ef = Ei

1/2mVf² + mghf = mghi

inputting values of hf and hi we have

Vf = √(2g(hi -hf)) = 7.14 m/s

Vf = 7.14 m/s

(c). From answer in option a and c, we can see there were no changes in the answers.

The Richter scale is used to determine how strong the earthquake is (magnitude) of the earthquake. It touches the ground and feels the earth shaking. With the momentum of the earth shaking the device the needle on the device moves creating a wave looking line. According to the theory of plate tectonics, what happens at transform, divergent and convergent boundaries? On which of these boundary types would a volcano most likely take place, and why?

Answers

convergent, because it is where the tectonic plates shove themselves together usually resulting in a mountain or volcano

Final answer:

In plate tectonics theory, transform boundaries occur when two plates slide past each other, divergent boundaries occur when two plates move away from each other, and convergent boundaries occur when two plates collide. A volcano is most likely to occur at a divergent boundary because the plates move away from each other, allowing magma from the mantle to reach the surface and create new crust.

Explanation:

In plate tectonics theory, Transform boundaries occur when two plates slide past each other horizontally, creating earthquakes. Divergent boundaries occur when two plates move away from each other, creating volcanic activity.

Convergent boundaries occur when two plates collide, and depending on the type of plates involved, can result in volcanic activity as one plate is forced beneath the other.

A volcano is most likely to occur at a divergent boundary because the plates move away from each other, allowing magma from the mantle to reach the surface and create new crust.

The Richter scale indicates the magnitude of an earthquake. The figure drawn by the needle during shaking is an outcome of earthquake's energy. This energy is what results in seismic waves travelling through various layers of earth causing shaking on the surface.

Learn more about Plate tectonics and volcanoes here:

brainly.com/question/33604065

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Which is the SI base unit for mass?

Answers

Answer:

kilogram

Explanation:

Answer:

SI base units of mass=KG

What is science? Plz help I cant find a answer thats not really complicated and i have to fit it within 3 sentences.

Answers

Science is the study of our universe, and our own planet. It is the study of the biological, chemical and physical world we live in. It is a process of discovering by experimenting and looking for patterns.

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