A woman is pushing a sofa at constant speed of 1.0 m/s on a horizontal surface. She exerts a horizontal force of 80 N in the direction of motion.
A) how can the sofa move at constant speed without Newton's first law being violated?
B)Approximately how hard would the woman have to push to keep the sofa moving at a constant speed of 2.0 m/s? explain
A) Newton's first law states that an object will remain at rest or move in a straight line with constant speed unless acted upon by an external force. In this scenario, the woman is exerting a horizontal force of 80 N in the direction of motion. This force counters the force of friction acting on the sofa, allowing it to move at a constant speed without violating Newton's first law. The force of friction is equal in magnitude and opposite in direction to the applied force, resulting in a net force of zero. This balance of forces allows the sofa to continue moving without any change in its speed.
B) To calculate approximately how hard the woman would have to push to keep the sofa moving at a constant speed of 2.0 m/s, we need to consider the relationship between force, mass, and acceleration.
The formula to calculate force is:
Force = mass × acceleration
Since the sofa is moving at a constant speed, its acceleration is zero. Therefore, the force required to keep it moving at a constant speed is also zero. This means the woman wouldn't have to exert any additional force to maintain the sofa's speed at 2.0 m/s once it's already in motion.
However, it is important to note that this assumes there are no other forces acting on the sofa, such as air resistance or additional friction. In reality, there would likely be some opposing forces that would require the woman to exert a certain amount of force to overcome them and maintain the constant speed of 2.0 m/s.
Who says that Newton's law is violated?
I will be happy to critique your thinking.