Answer:
The answer is 4th choice. Down with a speed less than v.
Explanation:
The momentum of the person and the balloon need to cancel each other out. Momentum formula of the balloon is as following:
At the moment of t=0, the person and the balloon has the 0 speed.
When the person starts to climb on a balloon, balloon need to cancel this momentum out. We know that the balloon is more heavier than the person. So balloon need to go down with the speed of less than v.
I believe your answer is d).
Hope you find this helpful! :)
Answer:
<em>faster and at a higher luminosity and temperature.</em>
Explanation:
A protostar looks like a star but its core is not yet hot enough for fusion to take place. The luminosity comes exclusively from the heating of the protostar as it contracts. Protostars are usually surrounded by dust, which blocks the light that they emit, so they are difficult to observe in the visible spectrum.
A protostar becomes a main sequence star when its core temperature exceeds 10 million K. This is the temperature needed for hydrogen fusion to operate efficiently.
Stars above about 200 solar masses (Higher mass) generate power so furiously that gravity cannot contain their internal pressure. These stars blow themselves apart and do not exist for long if at all. A protostar with less than 0.08 solar masses never reaches the 10 million K temperature needed for efficient hydrogen fusion. These result in “failed stars” called brown dwarfs which radiate mainly in the infrared and look deep red in color. They are very dim and difficult to detect, but there might be many of them, and in fact they might outnumber other stars in the universe.
That is why higher mass protostars enter the main sequence at a <em>faster and at a higher luminosity and temperature.</em>
Answer:
Explanation:
1. The gravitational force is related to the mass of each object.
This is true, the gravitational force between the two objects is directly proportional to the product of masses of two objects.
2. The gravitational force on a satellite is less at an altitude of 500 km above the Earth than at an altitude of 1000 km.
It is false, as the gravitational force between two objects is inversely proportional to the square of distance between them. The objects at more height has less gravitational force.
3. The gravitational force between the Earth and a person is constant, no matter how high the person is above the surface of the Earth.
It is false, because as we go on heights the value of acceleration due to gravity decreases.
Given:
Water, 2 kilograms
T1 = 20 degrees Celsius, T2 = 100
degrees Celsius.
Required:
Heat produced
Solution:
Q (heat) = nRT = nR(T2 = T1)
Q (heat) = 2 kilograms (4.184 kiloJoules
per kilogram Celsius) (100 degrees Celsius – 20 degrees Celsius)
<u>Q (heat) = 669.42 Joules
</u>This is the amount of heat
produced in boiling 2 kg of water.