Answer:
83.2 W/m^2
Explanation:
The radiation per unit area of a star is directly proportional to the power emitted, which is given by Stefan-Boltzmann law:
where
is the Stefan-Boltzmann constant
A is the surface area
T is the surface temperature
So, we see that the radiation per unit area is proportional to the fourth power of the temperature:
So in our problem we can write:
where
is the power per unit area of the present sun
is the temperature of the sun
is the power per unit area of sun X
is the temperature of sun X
Solving for I2, we find
Answer: acceleration is equal to the change in velocity per unit time in seconds.
a= ∆v / t = vf - vi / t
Explanation: change in velocity or ∆v can be expressed as (vf - vi)
Answer:
The velocity of the leaf relative to the jogger is 5 m/s.
Explanation:
Given that,
Velocity of jogger wrt to the ground, 
velocity of leaf wrt the ground, 
We need to find the velocity of the leaf relative to the jogger. Let it is equal to V. So, it is given by :
So, the velocity of the leaf relative to the jogger is 5 m/s. Hence, this is the required solution.
The viscous force on an object moving through air is proportional to its velocity.
The only forces acting on an object when falling are air resistance and its weight itself. The weight acts vertically downwards whereas air resistance acts vertically upward.
Let F be the viscous force due to air molecules, B be buoyant force due to air and W be the weight of falling object. Initially, the velocity of falling object and hence the viscous force F is zero and the object is accelerated due to force
(W-B). Because of the acceleration the velocity increases and accordingly the viscous force also increases. At a certain instant, the viscous force becomes equal to W-B. The net force then becomes zero and the object falls with constant velocity. This constant velocity is called terminal velocity.
Thus at terminal velocity, air resistance and force of gravity becomes equal.
