Explanation:
 
Show that the motion of a mass attached to the end of a spring is SHM
 
 
 Consider a mass "m" attached to the end of an elastic spring. The other end of the spring is fixed
 at the a firm support as shown in figure "a". The whole system is placed on a smooth horizontal surface.
 If we displace the mass 'm' from its mean position 'O' to point "a" by applying an external force, it is displaced by '+x' to its right, there will be elastic restring force on the mass equal to F in the left side which is applied by the spring.
 According to "Hook's Law
F = - Kx ---- (1)
 Negative sign indicates that the elastic restoring force is opposite to the displacement.
 Where K= Spring Constant
 If we release mass 'm' at point 'a', it moves forward to ' O'. At point ' O' it will not stop but moves forward towards point "b" due to inertia and covers the same displacement -x. At point 'b' once again elastic restoring force 'F' acts upon it but now in the right side. In this way it continues its motion
 from a to b and then b to a.
 According to Newton's 2nd law of motion, force 'F' produces acceleration 'a' in the body which is given by
F = ma ---- (2)
 Comparing equation (1) & (2)
ma = -kx
 Here k/m is constant term, therefore ,
a = - (Constant)x
or
a a -x
 This relation indicates that the acceleration of body attached to the end elastic spring is directly proportional to its displacement. Therefore its motion is Simple Harmonic Motion.
 
        
             
        
        
        
Answer:
0.79 s
Explanation:
We have to calculate the employee acceleration, in order to know the minimum time. According to Newton's second law:

The frictional force is maximum since the employee has to apply a maximum force to spend the minimum time. In y axis the employee's acceleration is zero, so the net force is zero. Recall that 
Now, we find the acceleration:

Finally, using an uniformly accelerated motion formula, we can calculate the minimum time. The employee starts at rest, thus his initial speed is zero:

 
        
             
        
        
        
Answer:


Explanation:
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
 = Mass of sphere = 2000 kg
 = Mass of sphere = 2000 kg
 = Mass of other sphere = 2.1 kg
 = Mass of other sphere = 2.1 kg
r = Distance between spheres
Force of gravity is given by

The gravitational force is 

The gravitational force is 
 
        
             
        
        
        
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