What happens if the forces acting on an object are balanced

The ground pushes up against the object. The reaction force is what you feel in your feet as you stand still. Without this balancing force you would sink into the ground. Balanced forces When two forces acting on an object are equal in size but act in opposite directions, we say that they are balanced forces.

If the forces on an object are balanced or if there are no forces acting on it , this is what happens: a stationary object stays still a moving object continues to move at the same speed and in the same direction Remember that an object can be moving, even if there are no forces acting on it.

Force diagrams We can show the forces acting on an object using a force diagram. The arrow shows: the size of the force the longer the arrow, the bigger the force the direction in which the force acts The arrow should be labelled with the name of the force and its size in newtons. Hanging objects The forces on this hanging crate are equal in size but act in opposite directions. Upon hitting the water, the box experience a balance of forces 50 N downwards due to gravity and 50 N upwards due to the water.

Diagram A depicts both the initial downward acceleration and the final constant velocity. Several of Luke's friends were watching the motion of the falling box. Being "physics types", they began discussing the motion and made the following comments. Indicate whether each of the comments is correct or incorrect? Support your answers. Once the box hits the water, the forces are balanced 50 N down and 50 N up. However, an object in motion such as the box will continue in motion at the same speed and in the same direction.

When the box strikes the water, it stops accelerating; yet it does not stop moving. Once the box hit the water, the forces are balanced 50 N down and 50 N up. The upward force of the water on the box is balanced by the downward pull of gravity. The box will continue in motion at constant speed. The box would only bounce upwards if the water applied an upward force greater than 50 N. As stated in the problem, the water applies only 50 N of upward force.

Furthermore, the upward force would first contribute to slowing the box down an upward acceleration before it could begin to actually move it upward. The answer could be A but does not have to be A and it could be B but does not have to be B. An object having balanced forces definitely cannot be accelerating. This means that it could be at rest and staying at rest one option or could be in motion at constant velocity a second option.

Either way, it definitely is not accelerating - choice C of your four choices. Physics Tutorial. My Cart Subscription Selection. Student Extras. Unbalanced Forces. We Would Like to Suggest Sometimes it isn't enough to just read about it. You have to interact with it! And that's exactly what you do when you use one of The Physics Classroom's Interactives.

It does not allow a body in motion to even change its direction or increase its speed too. Hanging Objects:. In the above picture the weight of the bulb shade pulls down and the tension in the thread pulls up. The forces pulling up and pulling down can be said to be in balance. Floating Objects:. In the above picture, the log is floating in the pool of water.

It is floating because the weight of the log is balanced by the up raise from the water. If more weight is tied to the log, the force that is pulling it down may be more and will cause it to sink. In the above picture, a metal block is seen resting on the surface of a table. The weight is balanced by the reaction force from the surface. As seen in the picture there are two forces acting upon the book. The other force pushes of the table on the book referred to as normal force pushes the book upward.

Since these two forces are of equal magnitude an in the opposite direction, they balance each other. The book is said to be in equilibrium. There is no unbalanced force acting upon the book as shown in the picture above and thus the book maintains its state of motion.

The greater the mass of a body, the greater will be its inertia and the greater will be its resistance to changes to its state of motion or rest. A body at rest implies that the net resultant force applied on the body is zero. However, it is not necessarily that there is no force acting on the body. In the above-given picture, a box is seen resting on a table has zero net resultant force.

But there are two forces acting on the box given above. One of the forces is the gravitational force due to the weight of the box, while the other is the normal force. The normal force is an external force exerted perpendicularly by the surface in reaction to anybody placed against it. Role of Friction:. The friction can be explained with the example of a shopping cart and how it is not balanced.

If a shopping cart gave a good push and let go, it does not go in a constant velocity forever. After a while the shopping cart you are no longer touching it to apply an unbalanced force. The ground has friction applies a force to the shopping cart to slow it down to a stop. So the shopping cart is not really an example of balanced forces. The Resultant Force and Balanced Force:.

Forces have direction and size. The forces are represented by arrows in the picture given above, i. The length of the arrow given the picture represents the size of the force. When an object has several forces acting on it, the effect of the force is the same as one force in a certain direction.

This is called the resultant force. If the resultant force is zero the force on the object are balanced. A resultant force is needed to change the velocity of an object or body. If the forces on an object are balanced then it will remain stationary, or if it is moving, it will continue to move at a steady speed in the same direction. This seems to be strange as we are used to frictional forces slowing things down.

What are Balanced Forces Equivalent To? Forces are said to be balanced if there are equal forces acting in opposite directions.