Answer:
When air resistance equals the weight of an object, the object has reached free fall.
Explanation:
- When an object has only force acting on it as gravity then, it experiences free fall.
- During free fall all the forces except gravity is balanced by one another.
- In the question, object's weight is balanced by air resistance so it is in the state of free fall.
- At the null point of free fall, object experiences weightlessness i.e. it feels like object is not attracted by any force.  
 
        
             
        
        
        
The If a car is going round a curve , there is an acceleration because the direction of the velocity changes.
<h3>What is the direction of the velocity?</h3>
Now we know that if you throw the ball upwards, the motion is in opposite direction to gravity thus the ball is experiencing deceleration and the speed decreases. The velocity decreases and the acceleration is negative.
If the ball is coming down, then the ball is accelerated thus it speeds up and the direction of the acceleration is positive.
If a car is going round a curve, the vehicle is accelerating because the direction of the velocity changes even if its amount remains constant.
When a board is moving down a hill at 2 ms-1, it is experiencing an acceleration because the motion is in the same direction as gravity.
If a car is coming to a stop at a point, it experiences a deceleration and not an acceleration since the change of velocity with time is negative as the car comes to rest.
Learn more about acceleration:brainly.com/question/12550364
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V=at and a=F/m
140/.070 = 2000m/s^2
2000*.020 = 40m/s
The ball’s velocity increased by 40m/s.
        
             
        
        
        
Because melting point<span> and </span>freezing point<span> describe the</span>same<span> transition of matter, in this case from liquid to solid (</span>freezing) or equivalently, from solid to liquid (melting<span>).</span>