From the moment it leaves a player’s hand, the only forces acting on it are gravity (vertically downwards) and air resistance (opposing the direction of motion). Gravity causes the ball to accelerate downwards throughout its flight. Unbalanced forces of gravity and air resistance are the only forces acting.

Archimedes Principle

The three forces acting on a hot-air balloon that is moving vertically are its weight, the force due to air resistance and the upthrust force. The three forces acting on a hot-air balloon that is moving vertically are its weight, the force due to air resistance and the upthrust force.

Friction – the force that is preventing the ball from moving on and on and on. “When you roll a ball on the ground, the electrons in the atoms on the surface of the ground push against the electrons in the atoms on the surface of your ball that is touching the ground.

If you kick a football and it moves from one place to another, it means that unbalanced forces are acting upon it. Ball moves from one place to another after kicking it. This is an example of unbalanced force.

Examples of unbalanced forces

• Kicking a soccer ball.
• The up and down movement in a seesaw.
• The taking-off of a Rocket.
• Skiing along the mountain slopes.
• Hitting a baseball.
• A turning vehicle.
• Drowning of an object.
• Apple falling on the ground.

5 Brilliant Examples of Balanced Forces

• Pushing against a wall.
• A game of tug of war with equally matched opponents.
• A book lying on a table.
• Running of a vehicle at uniform velocity.
• Sitting on a chair.
• Objects in hanging position.
• Objects in the floating position.
• Objects standing/sitting on a surface.

If you push against a wall, the wall pushes back with an equal but opposite force. Neither you nor the wall will move. Forces that cause a change in the motion of an object are unbalanced forces.

Here are some examples of situations involving balanced forces.

• Hanging objects. The forces on this hanging crate are equal in size but act in opposite directions.
• Floating in water. Objects float in water when their weight is balanced by the upthrust from the water.
• Standing on the ground.

EXAMPLE OF BALANCED AND UNBALANCED FORCES

• Forces have direction. To steer the hovercraft, Zoe needed a way to change the direction of the force.
• Forces can be balanced or unbalanced. Tug-of-war is a great example of balanced and unbalanced forces.
• Gravity pulls objects down.

When you sit in a chair, you are in equilibrium. The support force acting on you balances out your weight. As the name suggests, unbalanced forces is where one force is greater than the other, acting in the opposite direction.

When we push or pull an object we can make it move. If we push the car we make it move because our push is greater than the other forces acting upon it. If, on the other hand, an object is moving at a constant speed in a straight line then again the forces are said to be balanced.

For example, when an apple hangs from a tree, the weight of the apple is balanced by the force exerted by the branch on the apple. When an object is moving with changing speed, the net force on it is unbalanced.

An object is travelling at a steady or constant speed when its instantaneous speed has the same value throughout its journey. For example, if a car is travelling at a constant speed the reading on the car’s speedometer does not change.

Once moving, if there is no friction, then the object will continue to move at a constant speed unaided. The driving force balances the effect of friction. When this happens, there is no resultant force acting on the object, but this doesn’t mean that there are no forces at all.

the answers to your question are rather well understood. There the frictional force is proportional to the velocity for small velocities. For solid-on-solid friction, described by a ‘friction coefficient’, the friction force is pretty nearly independent of relative velocity for some range of relative velocity.