A 55 kg astronaut who weighs 170 N on a distant planet is pondering whether she can leap over a 4.0-m-wide chasm without falling in.

If she leaps at a 15∘ angle, what initial speed does she need to clear the chasm? v=?

What are the biological and radiological properties of xeon 133 and Gallium 67. For radiological imaging with the gamma camera.

An automobile is traveling on a long, straight highway at a steady 75.0 m/h when the driver sees a wreck 170 m ahead. At that instant, she applies the brakes (ignore reaction time). Between her and the wreck are two different surfaces. First there is 140 m of ice, where the deceleration is only 1.20 m/s^2 . From then on, it is dry concrete, where the deceleration is a more normal 7.90 m/s^2 . What was the car’s speed just after leaving the icy portion of the road? What is the total distance her car travels before it comes to a stop? What is the total time it took the car to stop?

A lead ball is dropped into a lake from a diving board 12.0 ft above the water. It hits the water with a certain velocity and then sinks to the bottom with this same constant velocity. If it reaches the bottom 5.30 s after it is dropped, how deep is the lake (in feet)?

A particle leaves the origin with an initial velocity of 4.10 m/s in the x direction, and moves with constant acceleration ax = -1.40 m/s2 and ay = 3.80 m/s2. How far does the particle move in the x direction before turning around? What is the particle's velocity at this time? Enter the x component first, followed by the y component.

A rubber ball is tossed straight up from a height of 10 feet with a velocity of 78 feet per second. The first time it hits the ground (y = 0), it rebounds with a velocity of 64 feet per second2 . The second time it hits the floor, it rebounds with a velocity of 48 feet per second. Before the first bounce 1. Find the function y = h1(t) for the height of the ball before its first bounce. 2. Find the time t1 when the ball hits the ground for the first time. The function h1(t) then describes the height of the ball over the time interval [0, t1] before the ball’s first bounce. 3. Find the velocity v1(t) of the ball over the interval [0, t1]. 4. Determine the time t when the ball reaches its first peak height. What is the height of the ball at this time? Between the first and second bounce 5. Find the function y = h2(t) for the height of the ball between the first and second bounce. 6. Find the time t2 when the ball hits the ground for the second time. The function h2(t) then describes the height of the ball over the time interval [t1, t2]. 7. Find the velocity v2(t) of the ball over the interval [t1, t2]. 8. Determine the time t when the ball reaches its second peak height. What is the height of the ball at this time? Between the second and third bounce 9. Find the function y = h3(t) for the height of the ball between the second and third bounce. 10. Find the time t3 when the ball hits the ground for the third time. The function h3(t) then describes the height of the ball over the time interval [t2, t3]. 11. Find the velocity v3(t) of the ball over the interval [t2, t3]. 12. Determine the time t when the ball reaches its third peak height. What is the height of the ball at this time? Graphs 13. On the coordinate systems below sketch accurate graphs of the height and velocity of the ball over the time interval [0, t3].

1- According to Plato, science can only give us opinions, not knowledge. Do you agree? Why or why not?

2- After reading Googling is Believing, what solutions might you present to the author's concerns regarding about our "faith in the idea of an informed citizenry"?

ANSWER EACH QUESTION WITH A MINIMUM OF 200 WORDS.

How many 25 cm stair steps would a 80 kg person need to climb to gain the same ammount of potential energy as provided by a can of coke wich has 140 calories.

1. A submarine (sub A) travels through water at a speed of 8.00 m/s, emitting a sonar wave at a frequency of 1,400 Hz. The speed of sound in the water is 1,533 m/s. A second submarine (sub B) is locate such that both submarines are traveling directly towards each other. The second submarine is moving at 9.00 m/s a) What frequency is detected by an observer riding on sub B as the submarines approach each other?

b) The submarines barely miss each other and pass. What frequency is detected by an observer riding on Sub B as the submarines recede from each other?

c) While the submarines are approaching each other some of the sound from sub A reflects from sub B and returns to sub A. If this sound were to be detected by an observer in sub A, what is its frequency?

2. By how much does the length of Dublin’s spire increase if its temperature increases from 0 to 20C? Assume the spire is 121 m long at 0 C and is made from stainless steel (α=12x10^-6 C-1) .

Which one of the following is not attracted or repelled by charged objects?

1. An electric field (in v/m) varies with postion along the y axis according to E = 1/y. Find the electric potential difference V_AB if A is a point on the y axis at y = 5 m and B is a point on the y axis at y = 7 ?

1. V_AB = 0.28 volts
2. V_AB = 0.34 volts
3. V_AB = 0.49 volts
4. V_AB = 0.82 volts

2. How does the electric potential at a point x, a finite distance away from a large positive charge, compare to a point x/2 from the charge?

1. The potential is half as big
2. The potential is twice as big
3. It depends upon the amount of charge
4. It depends upon the magnitude of x

3.

2. Which of the following doesn't depend upon the charge that moves from one point in an electric field to another?

1. The change in electric potential energy
2. The work done by the E-field
3. The change in electric potential
4. The change in kinetic energy

Ideal Gas equation.

I understand why PV=MRT but what i dont understand is. Why in this problem P1*V1/M1*R1*T1=P2*V2/M2*R2*T2

https://www.chegg.com/homework-help/Thermodynamics-8th-edition-chapter-7-problem-89P-solution-9780073398174

A 50 cm long rod is half aluminum and half copper. The aluminum end is in boiling water. The end of an aluminum rod (50 cm long) is maintained at 100 C by immersing in a pot of boiling water and the other end at 00C by an ice-water mixture. If the cross-sectional area of the rod is 1.3 cm2, how much will the rod melt in 20 min? What will be the steady temperature at the Al-Cu junction?

Instructions

Identify a current problem in physics by searching for news articles and current events. One reputable source of news in physics is Phys.org. Choose one article, and in two pages, describe how the scientific method is being used to solve the problem mentioned in the article. Identify the initial observations that identified the problem, the hypothesis, tests, and any revisions of the original hypothesis. Cite the article in APA format as well as other references you might use.

LINK:
https://phys.org/physics-news/