Conduction has to be touching the two objects. Convection is not direct.
        
                    
             
        
        
        
Answer:
Explanation:
Given
mass of person is m
Distance between bridge and river is h
chord has an un-stretched length of 
Let spring constant be k
Person will just stop before hitting the river
Conserve energy i.e. Potential Energy of Person is converted in to elastic energy of chord




Thus 
 
        
             
        
        
        
Answer:
As b ∝ (L/r²) and
the distance of the sun from the earth is 0.00001581 light years
and
 the distance of the Sirius from the earth is 8.6 light years
hence,
the Sun appear brighter in the sky
Explanation:
The brightness (b) is directly proportional to the Luminosity of the star (L) and inversely proportional to the square of the distance between the star and the observer (r).
thus, mathematically,
b ∝ (L/r²)
now,
given 
L for sirius is 23 times more than the sun i.e 23L
now, 
the distance of the sun from the earth is 0.00001581 light years
and
 the distance of the Sirius from the earth is 8.6 light years
thus,
using the the relation between conclude that the value of brightness for the Sirius comes very very low as compared to the value for brightness for the Sun.
hence, the sun appears brighter
 
        
             
        
        
        
Answer:
P = 10 kPa
Explanation:
Given that,
The mass of a small table, m = 4 kg
The area of each leg = 0.001 m²
We need to find the pressure exerted by the table on the floor. Pressure is equal to the force per unit area. So

So, the required pressure is 10 kPa.
 
        
             
        
        
        
Planets in our solar system do not revolve around the sun in perfect circles. Their orbits are more like ovals that scientists describe as elliptical. It is one of Kepler's laws. The sun is the focus of all the planets. The correct answer is D.