The second one if it’s on edge
The physical law that explains that is the law of conservation of energy which states that he energy of an isolated sistem remains constant
Answer:
Explanation:
When we apply a horizontal force of 76 N to a block, the block moves across the floor at a constant speed. So net force on the block is zero .
It implies that a force ( frictional ) acts on it which is equal to 76 N in opposite direction ( friction )
When we apply a greater force on it it starts moving with acceleration .
This time kinetic friction acts on it due to rough ground equal to 76 N .This is limiting friction ( maximum friction )
Net force on the body in later case
= 89 - 76
= 13 N
Force by ground on the block in horizontal direction = 76 N ( FRICTIONAL FORCE )
=
Answer:
Therefore the surface area of the balloon is increased at 4 cm³/s.
Explanation:
The balloon is being filled with air at a rate of 10 cm³/s
It means the volume of the balloon is increased at a rate 10 cm³/s.
i.e 
Consider r be the radius of the balloon.
The volume of of a sphere is
Differentiate with respect to t
The surface of area of the balloon is(S) = 
Differentiate with respect to t
Putting the value of 
Given that r = 5 cm
![[\frac{dS}{dt}]_{r=5} =\frac{20}{ 5}](https://tex.z-dn.net/?f=%5B%5Cfrac%7BdS%7D%7Bdt%7D%5D_%7Br%3D5%7D%20%3D%5Cfrac%7B20%7D%7B%205%7D)
=4 cm³/s
Therefore the surface area of the balloon is increased at 4 cm³/s.
Answer:
you divide the distance by the time it takes to travel that same distance, then you add your direction to it.
