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WorksheetsForces and Equilibrium
Total questions: 35
Worksheet time: 2hrs 32mins
State the principle of moments
A When a system is in equilibrium, the sum of the total clockwise moment is equal to the sum of the total anti-clockwise moment about the same pivot.
B When a system is in equilibrium, the sum of the total clockwise moment is greater the sum of the total anti-clockwise moment about the same pivot.
C When a system is in equilibrium, the sum of the total clockwise moment is less than the sum of the total anti-clockwise moment about the same pivot.
D When a system is in equilibrium, the sum of the total clockwise moment is equal to the sum of the total anti-clockwise moment about the different pivot.
The figure below shows a man lifting a heavy rock using a steel bar. He pushes downwards on the end of the bar with a force F. Which pivot positions allows the force F to be as small as possible?
Two masses of mass 10.0 and 6.0 kg are hung from massless strings at the end of a light rod. The rod is virtually weightless. A pivot (fulcrum) is placed off center and the system is free to rotate. If the 6.0 kg mass is 4.0 m away from the pivot, how far away is the 10.0 kg mass if the system is not rotating?
0.42 m
2.4 m
4.8 m
4.2 m
Assuming the system is in equilibrium, calculate the missing distance d
3.4 m
2.8 m
4.4 m
1.6 m
A boy of weight 600N sits on the see-saw as shown at a distance of 1.5m from the pivot. What is the force F required at the other end to balance the see-saw?
450 N
350 N
4.5 N
200 N
What is the size of the moment shown by the black arrow?
30 Nm
36 Nm
40 Nm
60 Nm
What to we call forces applied to anything that turns?
Minute
Moment
Minimum
Monument
What sense does the vector have?
down and right
up and left
up and right
down and left
What is the resultant vector's force?
10
20
-10
14.14
A heavy truck on wheels has a platform to attach to it. A man stands on the platform. The truck does not fall over.
Which position A, B, C, or D could be the centre of mass of the whole system (truck, platform and man) ?
A
B
C
D
A plane lamina with centre of mass X touches the ground at point P. Which diagram shows the lamina in equilibrium?
B
A
B
C
D
A
B
C
D
A
B
C
D
How many of these models will fall over?
1
2
3
4
All of the models
Center of gravity is usually located where
more weight is concentrated
less weight is concentrated
less mass is concentrated
more mass is concentrated
Where will be the centre of gravity of a uniform rod lies ?
At its end
At its middle point
At its centre of its cross sectional area
Depends upon its material
A simple method to find centre of gravity of a body is usage of
stop watch
plumbline
pendulum
gauge
Where do you hang the plumb line when determining the CG?
It doesn't matter, because it always goes through the CG
Only from the corners
From the point where you are suspending the object
At the right angle
What is the centre of gravity
The centre of the earth
An imaginary point at which weight is concentrated
Gravity
How objects fall to the ground.
Do all objects have a centre of gravity?
No objects have a centre of gravity
Only some objects have a centre of gravity
Only very heavy objects have a centre of gravity
Yes all objects have a centre of gravity
Two forces are acting on it as shown.
What is the net force acting on the plane?
8,000 N to the right.
8,000 N to the left.
13,000 N to the right.
13,000 N to the left.
A 2 kg falling object encounters 4-N of air resistance. The acceleration of the object is
-2 m/s2
2 m/s2
8 m/s2
16 m/s2
-8 m/s2
The free body diagram of four boxes are shown below. Which box is in equilibrium?
If an object is resting on a flat, horizontal surface, which of the following will be equal?
weight, mass
normal force, gravitational force
normal force, frictional force
gravitational force, frictional force
The diagram shows a box being pulled up the ramp. Which letter represents normal force?
A
B
C
D
Two soccer players kick a 200 g ball at the same time. One kicks it to the right with 150-N of force while the other kicks it to the left with 225-N of force. What is the acceleration of the ball?
375 m/s2 to the right
375 m/s2 to the left
0.375 m/s2 to the right
0.375 m/s2 to the left
Suzie holds an apple at rest in her outstretched hand. The force she applies in holding it still...
equals the weight of the apple.
is slightly more than the weight of the apple.
is slightly less than the weight of the apple.
is zero, until she drops the apple.
Burl and Paul have combined weights of 1300 N. The tensions in the supporting ropes that support the scaffold they stand on adds to 1700 N. What is the weight of the scaffold itself?
400 N
1300 N
1700 N
3000 N
A 100 cm uniform rod weighs 10 N and is pivoted at A as shown in the diagram.
What is the weight of object W if the reading on the spring balance is 19 N?
19.0 N
20.0 N
27.1 N
63.3 N
