Question

*Revision test of Ch-4(Force and Pressure)*

Q.1. Write two points of differences between balanced and unbalanced force.
Q.2. Write any two effects of force giving examples
Q.3. How Force and Pressure are related to each other?
Q.4. Write any three characteristics of liquid Pressure.
Q.5. Write two types of contact and non- contact forces giving examples of each. plzzz guys give me ans​

Answer 1

Explanation:

Q.1)

*Balanced force*- i) _pair of forces that are equal in magnitude but opposite in direction is called balanced force._

ii) _The resultant force is zero_

*Unbalanced force -* i) _unequal forces acting on a given object are called unbalanced force_

ii) _the resultant force is non zero_

Q2)

*Two effect of force with example are -*

i) *change in size/ shape of object.*

```Ex - squeezing a lemon to extract it's juice.```

ii) *change in the motion of an object.*

```Ex-a car moving to rest once its engine is switched off.```

Q3)

*Pressure is force exerted per unit area so both force and pressure are related to each other.*

Pressure = force / area

Q4)

Three characteristics of liquid pressure are -

i) liquid pressure increases with depth.

ii ) it depends on the density & height of the liquid.

iii) It acts equally in all directions.

Q5)

*Two types of contact force are*

i) *muscular force*

``` ( applying muscles to do any work)```

Ex - lifting brick from the ground and pulling bed.

ii) *frictional force*

```(Force between two surfaces in contact which acts opposite to the direction)```

Ex - riding a bicycle and rubbing both hands together to create heat.

*Two types of non contact force are-*

i) *gravitational force*

(The force of attraction between two object due to their masses)

```Ex- an Apple falling from a tree and earth orbiting around sun.```

ii) *electric force*

```(Force exerted by a charged body on another charged body)```

*Ex - glass rod rubbed with silk cloth and Balloons get attracted to another balloon when one of them are rubbed with hair.*

Answer 2

Answer:

u got ur answer already

❌❌❌here is ur answer (≧∇≦)←_←I see from the current columns of the daily press that "Professor Plumb, of the University of Chicago, has just invented a highly concentrated form of food. All the essential nutritive elements are put together in the form of pellets, each of which contains from one to two hundred times as much nourishment as an ounce of an ordinary article of diet. These pellets, diluted with water, will form all that is necessary to support life. The professor looks forward confidently to revolutionizing the present food system."

Now this kind of thing may be all very well in its way, but it is going to have its drawbacks as well. In the bright future anticipated by Professor Plumb, we can easily imagine such incidents as the following: