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Michael_25
- 5
- 0
Momentum of a body can be constant while it accelerates? I mean if velocity increases while mass decreases proportional.
And if is true, what force produces acceleration?
And if is true, what force produces acceleration?
An external force could cause it, but an external force is not needed. That acceleration could come from a variable specific impulse rocket. Consider a rocket in deep space, far removed from any external forces. The rate at which the rocket's momentum changes is ##\dot p = \dot m (v-v_e)##. So all we need to do to keep the momentum constant is to keep increasing the exhaust velocity ##v_e## in tune with the rocket's velocity ##v##.Michael_25 said:Yes, but what produces that acceleration?
D H said:An external force could cause it, but an external force is not needed. That acceleration could come from a variable specific impulse rocket. Consider a rocket in deep space, far removed from any external forces. The rate at which the rocket's momentum changes is ##\dot p = \dot m (v-v_e)##. So all we need to do to keep the momentum constant is to keep increasing the exhaust velocity ##v_e## in tune with the rocket's velocity ##v##.
It would be very unusual, but certainly not impossible provided the conditions above are met.Michael_25 said:In my opinion is a misconception that the initial momentum of a body can be constant while it accelerates.
Which is exactly what D H said in post 5 and A.T. said in post 6.Michael_25 said:Let be initial momentun of the body [itex]p_1=m_1v_1[/itex]. The body splites in two bodies, with the momentum [itex]p_2[/itex] and [itex]p_3[/itex], so that [itex]p_2+p_3=p_1[/itex].
If we put the condition [itex]p_1=p_2[/itex] = constant, then we got [itex]p_3=0[/itex].
This equation is only correct if ##\dot{m}=0##Michael_25 said:But we know to produce an acceleration we need a force [itex]F=\frac{dp}{dt}[/itex].
The constant momentum of an accelerated body is the property of an object in motion that determines the amount of force required to change its velocity. It is a measurement of the object's mass and velocity, and is conserved unless acted upon by an external force.
According to Newton's Second Law of Motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Therefore, a constant momentum indicates a constant mass and velocity, and any change in acceleration must be caused by an external force.
No, an object cannot have constant momentum and changing acceleration. As mentioned before, a change in acceleration requires an external force, which would also affect the object's momentum. In order for an object to have constant momentum, both its mass and velocity must remain unchanged.
An external force can cause a change in the velocity of an object, and therefore, a change in its momentum. This can be observed in everyday situations, such as a car accelerating or braking. The greater the force applied, the greater the change in momentum.
Constant momentum is important in physics because it is a fundamental concept that explains the behavior of objects in motion. It helps us understand the relationship between force, mass, and acceleration, and is essential in many areas of physics, including mechanics, thermodynamics, and electromagnetism.