. What causes a change in an object's motion?

Answer 1

A change in an object's motion is caused by forces acting upon it. Newton's second law of motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In other words, if there is a net force acting on an object, it will cause the object to accelerate or decelerate, resulting in a change in its motion.

Several factors can cause this change in motion:

1. Applied force: When a force is applied to an object, it can cause a change in its motion. For example, pushing a stationary object or applying force against its direction of motion can cause it to accelerate.

2. Friction: Friction is a force that opposes the relative motion between two surfaces in contact. It can cause a change in an object's motion by slowing it down or stopping it altogether.

3. Gravity: The force of gravity attracts objects towards each other. Near the Earth's surface, gravity causes objects to accelerate downwards. If an object is thrown upwards, gravity will act against its motion, causing it to slow down and eventually change direction.

4. Air resistance: When an object moves through a fluid medium like air, it experiences resistance known as air resistance. This force opposes the object's motion and can cause it to slow down or change direction.

5. Elastic forces: When an object is deformed, such as stretching a spring or compressing a ball, it can experience elastic forces. These forces can cause the object to return to its original shape or change its motion when released.

6. Inertia: Inertia is the resistance of an object to change its state of motion. If an object is at rest or already in motion, it tends to stay in that state unless acted upon by an external force.

In summary, any force acting on an object can cause a change in its motion, either by accelerating it, decelerating it, changing its direction, or deforming it.