An object moves in a straight line at a constant speed. Is it true that here must be no forces of any kind acting on this object? Explain.
the "net" force (sum of all forces acting on the object) must be zero
an airplane flying in a straight, level path
... lift equals gravity , thrust equals air resistance
No, it is not true that there must be no forces of any kind acting on an object that moves in a straight line at a constant speed. This is because an object can continue to move in a straight line at a constant speed even if forces are acting on it. However, the forces acting on the object must be balanced in such a way that the net force is zero.
According to Newton's first law of motion, an object will remain at rest or continue in a state of uniform motion in a straight line unless acted upon by an external force. So, if an object is moving in a straight line at a constant speed, it means that the forces acting on it are balanced, resulting in zero net force.
For example, if you push a book on a table, it moves in a straight line at a constant speed due to the force you apply. However, there are other forces at play, such as friction and the normal force from the table. These forces act in the opposite direction and balance out the force you apply, resulting in a net force of zero. As a result, the book can continue moving in a straight line at a constant speed.
In summary, an object moving in a straight line at a constant speed can have forces acting on it. However, these forces must be balanced in such a way that the net force is zero, allowing the object to maintain its motion.
Yes, it is true that there must be no net forces acting on an object moving in a straight line at a constant speed.
To explain this, we need to understand Newton's first law of motion, also known as the law of inertia. According to this law, an object at rest or in motion will continue to stay in its state of rest or motion unless acted upon by an external force. In other words, if an object is moving at a constant speed, it will continue moving in the same direction at the same speed unless a force is applied.
When there are no net forces acting on an object, the forces cancel each other out, resulting in a balanced condition. If the forces are balanced, the object will not accelerate or change its state of motion. Therefore, for an object to move in a straight line at a constant speed, all the applied forces on the object must be balanced or equal in magnitude and opposite in direction.
If any external force were to act on the object, it would cause an acceleration, leading to a change in velocity. This change could be in the form of an increase or decrease in speed or a change in direction. Hence, in order to maintain a constant speed and straight line motion, it is indeed necessary that there are no forces of any kind acting on the object.