Question

Why is an applied force necessary to keep most objects in the world moving at a constant velocity?

a) Because the object's weight acts to slow it down
b) Because a force is needed to accelerate an object
c) Because a frictional force opposing motion acts on most objects
d) Because the natural tendency of any object is to come to rest.

Answer 1

An applied force is necessary to counteract frictional force, which opposes motion and causes objects to slow down and stop.

Step-by-step explanation:

An applied force is necessary to keep most objects moving at a constant velocity primarily because of frictional force that opposes motion. According to Newton's first law of motion, an object will remain at rest or in uniform motion in a straight line unless acted upon by a net external force. In real-world situations, when you slide an object across a surface, it will typically slow down and stop due to the net force of friction. This friction is the resistance that objects encounter when moving over a surface. Hence, to maintain a constant velocity, an applied force is required to counteract this friction.

Now, if this object were on an ideal, frictionless surface, such as smooth ice, it would not require any additional force to maintain its velocity once a force to accelerate it had been applied. Once in motion, absent any opposing forces, the object would continue to move at the constant velocity imparted by the initial force, demonstrating Newton's first law.