Understanding Acceleration and Velocity in Relation to Gravitational Force

In summary, in order for an object to move with constant velocity, the acceleration must be 0 and the net force must be 0. This means that for an object weighing 20 Newtons to move upward at a constant velocity of 5 m/s, an upward force of 20 N must be applied to balance the downward force of gravity. The 5 m/s does not factor into this calculation. Additionally, as the object moves further away from the Earth's surface, the gravitational force decreases, meaning that less force is needed to maintain a constant velocity.
  • #1
cb767
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I can't believe I don't remember this. Is it possible to move upwards with a constant velocity? For example, if a block weighs 20 Newtons, and I want it to go at a constant velocity of 5 m/s , could I do that with a constant force? For some reason I don't think I can, but maybe I'm just screwing myself up somewhere...
 
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  • #2
Force= mass times acceleration. In order that something move with constant velocity it is necessary that the acceleration be 0 and so that the net force be 0. If an object weight 20 N. that means that there is a force of 20 Newtons downward. To balance that and get a net force of 0, you need an upward force of 20 N also. Notice that the "5 m/s" doesn't come into that. In order to move an object weighing 20 N upward at 5 m/s you must first apply a force greater than 20 N upward so there is an acceleration upward. When the speed gets to 5 m/s then you must reduce the upward force to exactly 20 N to keep that constant speed.
 
  • #3
Incidentally,your case would work out fine,if you were to drag the body with a constant force which would balance the friction force perfectly (i.e.no vertical movement).

Daniel.
 
  • #4
The amount of force needed to move upwards at constant velocity is the weight of the object.
 
  • #5
as u go further away from the Earth surface the gravitaional force will continously reduce .so even if u were to ignore the intial extra force applied there would still be an accelleration whose rate would increase the further u went from the earth
 

Related to Understanding Acceleration and Velocity in Relation to Gravitational Force

What is acceleration?

Acceleration is the rate of change of velocity over time. It is the measure of how quickly an object's speed or direction is changing.

How is acceleration calculated?

Acceleration can be calculated by dividing the change in velocity by the change in time. The formula for acceleration is a = Δv/Δt, where a is acceleration, Δv is the change in velocity, and Δt is the change in time.

What is the difference between average acceleration and instantaneous acceleration?

Average acceleration is the overall change in velocity over a certain period of time, while instantaneous acceleration is the acceleration at a specific moment in time. Average acceleration is calculated by dividing the final velocity by the initial velocity, while instantaneous acceleration is calculated by taking the derivative of the velocity function with respect to time.

What is velocity?

Velocity is the measure of an object's speed and direction. It is a vector quantity, meaning it has both magnitude (speed) and direction.

How is velocity different from speed?

Velocity and speed are often used interchangeably, but they have different meanings in physics. While speed is the rate of change of distance over time, velocity is the rate of change of displacement over time. This means that velocity takes into account the direction of motion, while speed does not.

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