- Why is force of gravity negative?
- Can kinetic energy of a system be increased?
- Can frictional force positive?
- How do you calculate work?
- How is work negative?
- Is work positive or negative zero?
- Can kinetic friction do positive work?
- What is positive example?
- What does it mean when work is 0?
- What is positive work done?
- Can work done by gravity be positive?
- What is positive work done with example?
- What are the examples of zero work done?
- Does kinetic friction speed up or slow down an object?
- In which process work done is zero?

## Why is force of gravity negative?

Towards the center of the Earth, the gravity is defined to the be negative.

At all points on the trajectory of a projectile, the gravitational acceleration points in the same direction, which is downwards toward the center of the Earth.

So, the sign for the gravitational acceleration is always negative..

## Can kinetic energy of a system be increased?

Answer ⇒ Yes, Kinetic Energy of the system can be increased without applying any External force on the system. Let us take an example to show that the kinetic energy can be increased without applying any external force. Keep the two Oppositely charged bodies at the certain distance.

## Can frictional force positive?

Friction, by its nature, always acts opposing the relative motion between two surfaces. work done by friction can be zero, when there is no relative motion. But positive work cannot be done under any circumstances, if you see it from a reference frame fixed to one of the two surfaces.

## How do you calculate work?

Work can be calculated with the equation: Work = Force × Distance. The SI unit for work is the joule (J), or Newton • meter (N • m). One joule equals the amount of work that is done when 1 N of force moves an object over a distance of 1 m.

## How is work negative?

Negative work occurs when the force acting on an object is opposite in direction to the displacement. So when you lower the book, you are applying an upwards force to it, but its displacement is downwards.

## Is work positive or negative zero?

We have seen the situations when the work done is zero. Work done can also be positive or negative. When 0o <= θ < 90o, work done is positive as Cos θ is positive. Work done by a force is positive if the applied force has a component in the direction of the displacement.

## Can kinetic friction do positive work?

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.

## What is positive example?

The definition of a positive is a good thing, or a result greater than zero, or something that represents an affirmation. An example of a positive is an item on a list of good things about losing your job. An example of a positive is a result on a pregnancy test saying that you’re pregnant. noun.

## What does it mean when work is 0?

Work is zero if applied force is zero (W=0 if F=0): If a block is moving on a smooth horizontal surface (frictionless), no work will be done. Note that the block may have large displacement but no work gets done.

## What is positive work done?

Work is the energy transferred from an agent applying a force to an object or into heat, and the net work done on an object is the total change of kinetic energy. Both positive work and negative work have meaning: Positive work follows when the force has a component parallel to the displacement.

## Can work done by gravity be positive?

If the object goes up (the height increases so Δh is positive) then the work done by gravity is negative and tries to make the object’s KE decrease. If the object goes down (the height decreases so Δh is negative), the work done by gravity is positive so it tries to make the object’s KE increase.

## What is positive work done with example?

Positive work: when force and displacement are in the same direction, the work performed on an object is said to be positive work. Example: When a body moves on the horizontal surface, force and displacement act in the forward path. The work is done in this case known as Positive work.

## What are the examples of zero work done?

5 examples of zero workIf a block is moving on a smooth horizontal surface, no work is done.You are carrying two bags in your hands and not moving . … A person holds a bundle of hay over his head for 30 minutes and gets tired. … If you push a wall , but it does not move . … You sit on a chair for hours .More items…•

## Does kinetic friction speed up or slow down an object?

ANSWER: No! Kinetic friction does oppose the relative motion of two surfaces. If the one of these surfaces is stationary, then it will tend to slow down the moving object. Can friction ever speed things up?

## In which process work done is zero?

An isobaric expansion of a gas requires heat transfer to keep the pressure constant. An isochoric process is one in which the volume is held constant, meaning that the work done by the system will be zero.