Why are objects that fall near Earth's surface rarely in free fall?
1 answer:
Answer: Air exerts forces on falling objects near Earth's surface.
Explanation: Objects falling near the earth surface are rarely in free fall due to the force exerted by air on falling object near the earth( air resistance).
The acceleration of free fall tend to pull the body towards the earth surface while air resistance (drag) tends to act in the opposite direction.
Given that the weight of the body is always constant.
The drag acts in the upward direction, thereby negating the downward weight of the object.
From Newton's Second law:
Force = mass × acceleration due to gravity
Acceleration = force / mass
The net force acting on the object becomes :
(Downward weight - upward drag)
This hampers the free fall of the object due to gravity.
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Power can be defined as the rate at which work is accomplished.
Option D is the correct answer.
<h3></h3><h3>Power </h3>The work done by an object in a given time interval is called the power of that object.
Suppose an external force F is applied to any object for the time interval T seconds. Due to this external force, the object will perform some amount of work for the time T seconds. This work W done by the object for the time interval T seconds is called the power of that object.
Power can be defined in mathematical term which is given below.
Thus the power can also be defined as the work done by the object per unit time interval.
Hence we can conclude that option D is the correct answer.
To know more about power, follow the link given below.
We can solve the problem by using Newton's second law of motion:
where
F is the net force applied to the object
m is the object's mass
a is the acceleration of the object
In this problem, the force applied to the car is F=1050 N, while the mass of the car is m=760 kg. Therefore, we can rearrange the equation and put these numbers in, in order to find the acceleration of the car:
The equation also tells us that the acceleration and the force have same directions: therefore, since the force exerted on the car is horizontal, the correct answer is
<span>B) 1.4 m/s2 horizontally.</span>
where
F is the net force applied to the object
m is the object's mass
a is the acceleration of the object
In this problem, the force applied to the car is F=1050 N, while the mass of the car is m=760 kg. Therefore, we can rearrange the equation and put these numbers in, in order to find the acceleration of the car:
The equation also tells us that the acceleration and the force have same directions: therefore, since the force exerted on the car is horizontal, the correct answer is
<span>B) 1.4 m/s2 horizontally.</span>