Is the Sun an average star? Why or why not?
Our Sun is an average star. It is not the oldest star in our Galaxy, but it is not the youngest either; it is at an average age. It is not the hottest star in our galaxy, but it is not the coldest. It is not the biggest, but it is not the smallest. It is just another typical star, similar to all the others in the galaxy.
One watt is A. equal to one kilogram per second B. the power that can be delivered by an average horse C. the same as one-foot pound per second D. the proper replacement unit for one joule per second E. the same as one horsepower per second
D. the proper replacement unit for one joule per second
When energy is divided by the time the energy was used we get power
So, the answer is D. the proper replacement unit for one joule per second
A balloon is filled to a volume of 7.00*10^2 mL at a temperature of 20.0°C. The balloon is then cooled at constant pressure to a temperature of 1.00*10^2 K. What is the final volume of the balloon?
The final volume of the gas is 238.9 mL
We can solve this problem by using Charle's law, which states that for a gas kept at constant pressure, the volume of the gas (V) is proportional to its absolute temperature (T):
Which can be also re-written as
are the initial and final volumes of the gas
are the initial and final temperature of the gas
For the gas in the balloon in this problem, we have:
is the initial volume
is the initial absolute temperature
is the final volume
is the final temperature
Solving for ,
Learn more about ideal gases:
A 435-gram baseball traveling at 36 m/s is hit directly back at the pitcher with a speed of 49 m/s. If the force of contact between the bat and the ball is 3500 Newtons, then the ball is in contact with the bat for a time of_______________. A. 1.615714286
t = 0.0105 s
mass of the baseball = 435 g = 0.435 Kg
initial speed of ball, u = 36 m/s
final speed of ball, v = 49 m/s
contact force , F = 3500 N
Impulse is equal to change in momentum
I = m v - m u
I = 0.435 (49-(-36))
I = 0.435 x 85
I = 36.975 kg.m/s
we also know that
I = F x t
36.975 = 3500 x t
t = 0.0105 s
time of contact is equal to 0.0105 s
If you are asked to determine an object’s speed, what information must you have? A. distance and period of time
B. distance and change in position
C. period of time and direction
D. distance and direction
You raise a bucket of water from the bottom of a deep well. if your power output is 100 w, and the mass of the bucket and the water in it is 3.50 kg, with what speed can you raise the bucket? ignore the weight of the rope.
A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature of the gas is raised to 235 degrees kelvin, what is the new pressure of the gas? (Assume that there's no change in volume.) A. 854.46 kPa B. 510 kPa C. 3.636 kPa D. 1.702 kPa
A) 854.46 kPa
P₁ = initial pressure of the gas = 400 kPa
P₂ = final pressure of the gas = ?
T₁ = initial temperature of the gas = 110 K
T₂ = final temperature of the gas = 235 K
Using the equation
Inserting the values
P₂ = 854.46 kPa
Explain how fossil fuels are used to produce electricity?
Fossils are remains from animals and plants. They are embedded in rock and preserved in petrified form.
In a fossil fuels power plant carbon fuels such as oil, coal and gas are burnt to generate steam that are used to turn large turbines that generate electricity.
These turbines turn magnetic fields inside conductor inducing a large current in them.
Fossils fuels are much reliable as they can be used for a long period of time.
The absolute pressure below the surface of a freshwater lake is 3.51 x 10^5 Pa. At what depth does this pressure occur? Assume that atmospheric pressure is 1.01 x 10^5 Pa. and the density of the water is 1.00 x 10^3 kg/m^3