Take your time, do not get distracted , do not talk and focus on the exam
B is correct because most of the cells look the same so it's B
Answer: His third law states that for every action (force) in nature there is an equal and opposite reaction. In other words, if object A exerts a force on object B, then object B also exerts an equal and opposite force on object A.
Explanation:
Answer: 6,400 km
Explanation:
The weight of a person is given by:
where m is the mass of the person and g is the acceleration due to gravity. While the mass does not depend on the height above the surface, the value of g does, following the formula:
where
G is the gravitational constant
M is the Earth's mass
r is the distance of the person from the Earth's center
The problem says that the person weighs 800 N at the Earth's surface, so when r=R (Earth's radius):
(1)
Now we want to find the height h above the surface at which the weight of the man is 200 N:
(2)
If we divide eq.(1) by eq.(2), we get
By solving the equation, we find:
which has two solutions:
--> negative solution, we can ignore it
--> this is our solution
Since the Earth's radius is 
, the person should be at 
above Earth's surface.
Answer:
0·77 m
Explanation:
Given
Spring constant = k = 790 N/m
Equilibrium length of the spring = 48 cm = 0·48 m
Force applied = 230 N
Let the x m be the length of the spring when 230 N of force is applied on it
Spring force that is acting will be k × (x - 0·48)
<h3>Because spring force that is acting will be proportional to length from the equilibrium position</h3>
When applied force is 230 N, the spring force will also be equal to 230 N as there will be equilibrium
∴ k × (x - 0·48) = 230
790 × (x - 0·48) = 230
x = (230 ÷ 790) + 0·48
x = 0·29 + 0·48
∴ x = 0·77 m
∴ Length of the spring when 230 N of force is applied to stretch it = 0·77 m
