At time
seconds, the mass has angular speed

and hence linear speed

After 8 s, its linear speed is

and has centripetal acceleration with magnitude

To maintain this linear speed, by Newton's second law the required centripetal force should have magnitude

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Answer:g=9.79
,A object of mass

at the surface of earth experiences a force

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Explanation:
Let
be the mass of earth.
Let
be the radius of earth.
Let
be the universal gravitational constant.
Given,




Let
be the acceleration due to gravity.
Then,


A object of mass
at the surface of earth experiences a force 
Answer:
The balance between incoming energy from the sun and outgoing energy from Earth ultimately drives our climate. This energy balance is governed by the first law of thermodynamics, also known as the law of conservation of energy.
Answer:
Explanation:
A 40kg child throw stone of 0.5kg
At a direction of 5m/s
Recoil can be calculated using recoil of a gun formula
m_1•v_1 + m_2•v_2
m_1•v_1 = -m_2•v_2
The negative sign show that the momentum of the boy is directed oppositely to that of the stone
m_1 Is mass of boy
v_1 is the recoil velocity of the boy
m_2 is mass of stone
v_2 is the velocity of stone
Then,
m_1•v_1 = -m_2•v_2
40•v_1 = -0.5 × 5
40•v_1 = -2.5
v_1 = -2.5 / 40
v_1 = -0.0625 m/s
The recoil velocity of the boy is 0.0625 m/s
the electric force decreases because the distance has an indirect relationship to the force
Explanation:
The electric force between two objects is given by

where
k is the Coulomb's constant
q1 and q2 are the charges of the two objects
r is the distance between the two objects
As we can see from the formula, the magnitude of the force is inversely proportional to the square of the distance: so, when the distance between the object increases, the magnitude of the force decreases.