Force
Turning Effect of Force
Thrust and Solid Pressure
Liquid and Atmospheric Pressure
Numericals
100
The scientist who did a lot of research on force
Who is Sir Isaac Newton?
100
The definition of moment of force.
What is the moment of a force is equal to the product of the magnitude of the force and the perpendicular distance of the force from the pivoted point?
100
Define thrust
What is the force acting normally on surface?
100
The standard value of Atmospheric Pressure at mean sea level on earth.
What is 76 cm or 760 mm of Mercury column which is equal to 1 atm or 1.013 x 105 Pa
100
Calculate the distance of force from pivot if Moment of of force is 30 N m and Force = 5 N
Distance is 6 metres
200
The definition of Force
What is a push or pull which tends to result in movement or change in size/shape of a body?
200
Why does a spanner have a long handle?
A spanner has a long handle to produce a large turning effect by a small force applied at the end of the handle.
200
Give and define the S.I unit of pressure.
The unit of Pressure is pascal.(Pa)
1 pascal is the pressure exerted by by a thrust of 1 newton on a surcace of area 1 metre2.
200
What are the factors affecting liquid pressure?
There are two factors that affect fluid pressure. The first factor is the depth of the fluid: the exertion of the pressure by the fluid increases as the depth increases. The second factor is the density of the fluid: there is the exertion of more pressure by denser fluids like water in comparison to lighter fluids like air.
200
Find the momnent of force in S.I unit.
F=2 kgf
d=500 mm
10 N m
300
The relation between kgf and Newton
What is 1 kgf=10 N?
300
The factors affecting the turning of a body.
What is the magnitude of force applied and the perpendicular distance of the force from the pivoted point?
300
Give the 2 factors affecting pressure.
What are
1.The area of the surface on which thrust acts
2.The magnitude of thrust acting on the surface.
300
Why is the thickness of the walls of a dam increased towards to the bottom?
This is because pressure at a point due to a liquid increases with the increase in height of the liquid column above it,so thickness of the walls of a dam is increased towards the bottom so as to whithstand the increasing pressure of water.
300
A force of 1200 N acts on the surface of area 10 cm2 normally. What would be the thrust and pressure on the surface?
Thrust = 1200 N
Pressure=1.2 × 106 N/m2
400
The definition of the speed of a body.
What is the is the distance travelled by a body in a second?
400
How to change the direction of rotaion of a body.
The direction of rotation of a body can be changed by changing the point at which the force is applied or by changing the point at which the direction of the force is applied.
400
Differentiate between thrust and pressure.(3 points)
400
What is Hydrostatic Paradox?
The pressure at a certain horizontal level in the fluid is proportional to the vertical distance to the surface of the fluid or the phenomenon of a liquid seeking it's own level.
400
The elephant weighs 20,000 N stands on one foot of area 1000 cm2. How much pressure would it exert on the ground?
2,00,000 Pa
500
The mass and weight of a body on the moon,if the body has Mass 40 Kg and Weight 40 kgf on Earth.(Gravity on Moon is 1/6 of that on Earth).Explain.
What is 40 kg and 6.66 kgf?Why is the weight of a body dependent on gravitational pull but mass of a body always stays the same?
500
A force is applied through a pivoted point of a circular body.Will the body rotate? Give reasons.
No, the body will not rotate as
Turning effect = force x _of the force from the pivoted point.
Distance = O or force is parallel to the point of application of force.
So F x 0= 0
500
What is absolute pressure? Give an example.
The definition of absolute pressure is the pressure of having no matter inside a space, or a perfect vacuum. Measurements taken in absolute pressure use this absolute zero as their reference point. The best example of an absolute referenced pressure is the measurement of barometric pressure.
500
How do we measure atmospheric pressure?
The height of the mercury column is commonly used to measure atmospheric pressure. With sea level, the barometric height is 0.76m of Hg (or 76cm of Hg or 760mm of Hg) at normal temperature and pressure, which is equal to 1 atmosphere. As a result, atmospheric pressure is also measured in units of atmosphere.
1 atmospheric pressure (atm) = 0.76m of Hg = 1.013 * 105 Pa
500
The pressure of a gas contained in a cylinder with a movable piston is 300 Pa. The area of the piston is 0.5 m2. Calculate the force that is exerted on the piston.
150 N