Answer:
<em>The momentum of the car is 35,000 kg.m/s</em>
Explanation:
<u>Momentum</u>
Momentum is often defined as <em>mass in motion.</em>
Since all objects have mass, if it's moving, then it has momentum. It can be calculated as the product of the mass by the velocity of the object:

If only magnitudes are considered:
p = mv
The car has a mass of m=1,000 kg and travels at v=35 m/s. Calculating its momentum:
p = 1,000 kg * 35 m/s
p = 35,000 kg.m/s
The momentum of the car is 35,000 kg.m/s
 
        
             
        
        
        
In my view, correct answer should look like this: Although wave power does not produce pollution, some people may not want to invest in it because it is <span>prone to storm damage and limited to particular areas of the ocean.</span>
        
                    
             
        
        
        
Newton's second law states that the resultant of the forces applied to an object is equal to the product between the object's mass and its acceleration:

where in our problem, m is the mass the (child+cart) and a is the acceleration of the system.
We are only concerned about what it happens on the horizontal axis, so there are two forces acting on the cart+child system: the force F of the man pushing it, and the frictional force 

 acting in the opposite direction. So Newton's second law can be rewritten as

or

since the frictional force is 15 N and we want to achieve an acceleration of 

, we can substitute these values to find what is the force the man needs:
 
 
        
        
        
Explanation:
Amplitude, in physics, the maximum displacement or distance moved by a point on a vibrating body or wave measured from its equilibrium position. It is equal to one-half the length of the vibration path. ... Waves are generated by vibrating sources, their amplitude being proportional to the amplitude of the source.