If a body is in motion, some force, of necessity, acted upon it to get it moving in the first place. However, if no furtherforces are acting upon it, including, for example, friction, gravity or solar radiation as with an object traveling through space, for example, the object would tend to continue on its path, unaltered, ad infinitum.
Forces that likely act upon a moving object include:frictiongravity
To keep moving in a straight line. This is rather hard to show because the gravitational pull of the Earth is hard to escape without a rocket.
Then the result will be the same as if NO forces act on the object (since the sum of the forces is zero). The object will continue moving in a straight line, at constant speed.
If an object is already in motion, in principle it requires no force to remain moving.
When the entire group of forces acting on an object is balanced, the object's motion is 'uniform' ... its speed is constant and it moves in a straight line. If its speed is changing or its path is not straight, that's called "acceleration", and it means that the group of forces acting on the object is not balanced.
Intertia is the tendency of an object to maintain its velocity: if an object is at rest, it has the tendency to remain at rest; if it is moving, the tendency is to keep moving with the same velocity. That is what happens if no forces act on the object; if forces act on the object, including gravitation, friction, and others, its velocity will change.
Forces that likely act upon a moving object include:frictiongravity
To keep moving in a straight line. This is rather hard to show because the gravitational pull of the Earth is hard to escape without a rocket.
Inertia
Then the result will be the same as if NO forces act on the object (since the sum of the forces is zero). The object will continue moving in a straight line, at constant speed.
Yes.
If forces on an object are unbalanced, the object will accelerate or decelerate. If forces on an object are balanced, the object will stay still or keep moving with the same velocity.
It's not necessary to specify that the object is moving at a constant speed. Any object with no outside forces acting on it does that. It also continues moving in a straight line.
No resultant forces act upon it
Sure. If all of the forces on an object are balanced, then the object continues moving in a straight line at constant speed. All of the forces on an airplane cruising in level flight, or on a car on cruise-control on a straight piece of road, are balanced.
Water has high cohesive forces
Sure. If all of the forces on an object are balanced, then the object continues moving in a straight line at constant speed. All of the forces on an airplane cruising in level flight, or on a car on cruise-control on a straight piece of road, are balanced.