An insulated beaker with negligible mass contains liquid water with a mass of 0.250 kg and a temperature of 62.0 ∘C .

How much ice at a temperature of -25.0 ∘C must be dropped into the water so that the final temperature of the system will be 39.0 ∘C ?

Take the specific heat of liquid water to be 4190 J/kg⋅K , the specific heat of ice to be 2100 J/kg⋅K , and the heat of fusion for water to be 3.34×10⁵ J/kg .

It costs $180 to heat a house with electricity in a typical winter month. (Electric heat simply converts all the incoming electrical energy to heat.)

Part A

What would the monthly heating bill be following conversion to an electrically powered heat-pump system with COP=3.1?

1a.Summarize what Asteroid and Comet is

b. Do people think an Asteroid or Comet

Impact can be stop? Explain why

c. Do people think an Asteroid or Comet

Impact can notbe stop? Explain why

d. Do you personally think an Asteroid or Comet

Impact can be stop? Explain why.

A 62-kg bicyclist rides his 10.3-kg bicycle with a speed of 13.5 m/s. Assuming contant acceleration, (a) How much work must be done by the brakes to bring the bike and rider to a stop? kJ (b) How far does the bicycle travel if it takes 4.7 s to come to rest? m (c) What is the magnitude of the braking force? N

A thin uniform rod (mass = 0.420 kg) swings about an axis that passes through one end of the rod and is perpendicular to the plane of the swing. The rod swings with a period of 1.45 s and an angular amplitude of 10.6

13. When a single charge q is placed on one corner of a square, the electric field at the center of the square is F/q. If three other equal charges are placed on the other corners, the electric field at the center of the square due to these four equal charges is

A) F/(2q). B) F/(4q). C) 4F/q. D) F/q. E) None of the choices are correct.

14. Lightning (a flow of electrons between the ground and a thundercloud) lasts about 120µs. The rate of charge flow in a typical lightning bolt is about 25,000 coulombs per second.

A) How much total charge flows between the ground and the cloud during a typical lightning bolt?

B) How many electrons flow during this time?

It appears the most of the matter in the Universe is non-luminous, IE not part of stars.

a) Describe the experimental evidence for the existence of this dark matter.

b) What is this dark matter made of, according to current thinking?

Power is generated at 24 kV at a generating plant located 55km from a town that requires 60MW of power at 12 kV. Two transmission lines from the plant to the town each have a resistance of
0.11?/km .

What should the output voltage of the transformer at the generating plant be for an overall transmission efficiency of 97.8%, assuming a perfect transformer?

A water balloon is observed to emerge from an open window of a gymnasium. The window is 9.5 m above the ground. Through miracles of technology (involving doppler radar and automated video analysis), it is determined that the balloon leaves the window with a speed of 12.5 m/s at an angle of 45∘45∘ relative to horizontal.
(A) How much time elapses from when the balloon is passing through the window to when it hits the ground?  s
(B) How far from the wall does the balloon hit the ground?   m

It is determined that someone within the gymnasium threw the balloon from the floor level of the gymnasium,which is level with the ground outside.
(C) Assuming the launch point is from the floor level, how far from the wall was the balloon launched?  m

An object is launched from 2.3 meters above the ground with a 60 degree angle with the horizontal the ball collides with the earth at a distance of 20.5 meters

A) Calculate the maximum height
B) Calculate the initial speed.
C) Calculate the speed before impact

The pressure inside a commercial airliner is maintained at 1ATM (1.01x10⁵ N/m²). What is the outward force exerted on a 1mx2m cabin door if the outside pressure (at 10km high) is .3 ATM?

A proton and a singly charged ion of mass 91 atomic mass units (amu) are accelerated through the same potential difference and enter a region of uniform magnetic field moving perpendicular to the magnetic field. What is the ratio of their kinetic energies?  If the radius of the proton's circular path in the magnetic field is 16.8 cm , what is the radius of the path of the singly charged ion of 91 amu?  By what factor must the magnetic field be multiplied by for the singly charge ion to have the same radius path as the proton?

Is it possible, in principle, for you to travel to the center of the galaxy, which is 23,000ly away in your lifetime? Explain, using both time dilation and length contraction arguments. If your spaceship can go a maximum of v = 0.990c, will you make the one way trip in your lifetime? Let’s assume you have 80 years.

What is the difference between beats and echoes?