Table of Contents

## Can friction be made zero?

No , we cannot have zero friction surfaces . Even if we use a lot of lubricants , the friction will be reduced but can never be reduced to zero because every surface will still have minor irregularities in them.

### How do you find the normal force?

In this simple case of an object sitting on a horizontal surface, the normal force will be equal to the force of gravity F n = m g F_n=mg Fn=mgF, start subscript, n, end subscript, equals, m, g.

#### Does force of friction increase with acceleration?

As a force that opposes motion, friction always reduces acceleration.

**Can the work by kinetic friction on an object be positive or zero?**

Answer ‡’ Yes, work done by the kinetic friction on the object can be positive and also zero. Work done by the kinetic friction on an object is always the negative because the displacement is always opposite to the the frictional force.

**Can the force of kinetic friction do work?**

Kinetic Friction and Energy Furthermore, an internal kinetic friction force will always do net negative work due to the fact that the kinetic force requires that motion be taking place, and the direction of the net force is guaranteed to be directed opposite to that motion.

## Can work done by static friction be non-zero?

Answer ‡’ Yes. Static friction can do the non-zero work on the object. Static friction can do the non-zero work on the object. Non-zero work means the Positive work.

### Can work done by kinetic friction be 0?

Work done by kinetic friction on a body is never zero.

#### How do you find work done by kinetic friction?

The work done by friction is the force of friction times the distance traveled times the cosine of the angle between the friction force and displacement; hence, this gives us a way of finding the distance traveled after the person stops pushing.

**What is work done by static friction?**

if there is no slip between A and B then f is static and total work done by static friction on system is zero.

**Can normal force do a non zero work on an object?**

Answer ‡’ Yes, the Normal Force can do the non-zero work on the Object. When the Person is moving to the top from the Elevator, i.e. against the force of the gravity, the work done by the normal reaction force is negative. Negative work is also non-zero work since its magnitude is non the zero.

## Can a normal force on an object ever do work?

At the first-year physics level — absolutely a normal force can do work. If an object moves parallel (or antiparallel) to a normal force, then the normal force has done work. Even for a block sliding up or down an incline, the normal force does no work.

### Is there any other force for non zero work?

Explanation: If displacement and force are perpendicular to each other, work done is zero. a) When a body is in circular motion no work is done by centripetal force. b) In pulling a body on a horizontal surface, no work is done against gravitational force.

#### Can the normal force on an object over do work?

Can the normal force on an object ever do work? Yes, in certain circumstances normal force can do work. In an elevator, your contact force with your feet is a normal force. When moving upward it applies a force and moves you in the direction of the applied force.

**Is work done when you jump?**

When you jump into the air, the floor does work on you, increasing your kinetic and potential energy. No work is done by ground.

**Why is it tiring to push hard to a fix wall even though you are doing no work?**

Why is it tiring to push hard against a solid wall even though you are doing no work? It is tiring because even though their is no displacement by pushing on the solid wall, you are still exerting a force and expending energy in the process.

## Is normal force positive or negative?

Note that the normal force is in the upward (positive) direction, while gravitational acceleration and the force of gravity are in the downward (negative) direction. Use this to solve for the normal force.

### Can a normal be negative?

The normal reaction force is the force the ground exerts on the object to prevent the object from sinking into the ground. It can be zero. In which case, it would means that the object is floating just above the surface, not really touching it. But it cannot be negative.