Answer:
F = f from Newton’s first law.
Explanation:
since the desk is moved in a straight line at a constant speed, newton first law tell us that the two forces must be equal.
Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. since the table has been set in motion by the 400 N force, it will remain in motion unless it is been acted upon by an external force, and this means that the 400 N must be equal to the frictional force for it to have been in motion in the first instance.
Tornado- Trees knocked down, debris everywhere, ground and dirt scattered.
Answer:
Explanation:
Potential energy on the surface of the earth
= - GMm/ R
Potential at height h
= - GMm/ (R+h)
Potential difference
= GMm/ R - GMm/ (R+h)
= GMm ( 1/R - 1/ R+h )
= GMmh / R (R +h)
This will be the energy needed to launch an object from the surface of Earth to a height h above the surface.
Extra energy is needed to get the same object into orbit at height h
= Kinetic energy of the orbiting object at height h
= 1/2 x potential energy at height h
= 1/2 x GMm / ( R + h)
Answer:
a luminous ball of plasma
Answer: 0.62
Explanation:
Coefficient of friction is defined as the ratio of the moving force (Fm) acting on a body to the normal reaction (R).
Note that the normal reaction acts vertically on the object and is equal to the objects weight (W) i.e W=R
Since W = mg, W = 38.4 ×10
W= 384N =R
Normal reaction = 384N
The horizontal force acting on the body will be the moving force which is 238N
Coefficient of friction = Fm/R
Coefficient of friction = 238/384
Coefficient of friction = 0.62
Therefore, coefficient of kinetic friction between the box and the floor is 0.62