Force and Pressure Flashcards
(22 cards)
Define force
Force is am external agency that changes or tends to change the state of rest or motion of a body. The SI unit of force is newton (N).
What is the moment of force?
The turning effect of force about a fixed point is known as the turning effect of force.
What are the factors effecting force?
- Magnitude of the applied force
2. Perpendicular distance of the force from the pivot
What is the formula of the moment of force?
Moment of force(M)= f×d
(F is force applied and d is perpendicular distance between the pivot and the point of application of force.
What is the unit of moment of force?
Newton×metre (N×m).
The unit of moment of force in CGS system is dyne cm.
How are the SI unit and CGS unit of moment of force related.
1 Nm= 10⁵×10² cm
= 10⁷ dyne cm.
Explain the various applications of moment of force
- The driver of car applies force on the rim of the steering wheel to turn it.
Make your own examples.
Define pressure.
The force acting on a unit area of a surface.
What is thrust?
The perpendicular force acting on a surface is called thrust.
What is the unit of pressure?
The SI unit of pressure is N/m², which is also known as pascal (Pa).
1 Pa= 1N/1m²
Formula of pressure?
Pressure= force/area=thrust/area
List the factors affecting pressure
- The magnitude of force acting on the surface.
- The direction in which force is applied kn the surface
- The area of surface over which the force is applied.
Application of pressure in daily life
- School bags have straps to reduce weight on the shoulders/hand.
- All cutting and piercing tools have sharp edges that reduce the area of contact, thus they exert great pressure with comparatively less force.
Explain lateral pressure.
When the molecules of a liquid move, they collide with the walls of the container and exert pressure, this is called lateral pressure.
Explain the characteristics of liquid pressure
- Liquid pressure increases with depth.
- Liquid pressure remains the same in all directions at a given depth.
- Liquid pressure depends upon the density of the liquids.
- Liquid seek it own level
- Liquid exerts lateral pressure.
What are the effects of liquid pressure
The pressure increases in seas or oceans as their depths increases.
Define atmosphere
The envelope of air surrounding the earth.
Define atmospheric pressure
The pressure exerted by air.
What is the SI unit of atmospheric pressure
Pascal
What is the measured value of atmospheric pressure on the surface of the earth?
10⁵ pascal.
Instrument used to measure atmospheric pressure
Barometer
What are the effects of atmospheric pressure
- The working of a fountain pen is possible because of atmospheric pressure
