Worksheets14/01/2026 AE: EM: _FRICTION, DALEMBERT'S PRINCIPLE
Total questions: 10
Worksheet time: 5mins
A person with a mass of 75 kg is in a lift accelerating upwards at 2m/s2 . What is the apparent weight of the person? (Assume g=9.81m/s2 )
585.75 N
735.75 N
150 N
885.75 N
What is the primary analytical advantage of applying D'Alembert's Principle to a dynamics problem?
It increases the accuracy of the final calculation.
It transforms a dynamics problem into a static equilibrium problem.
It eliminates the need to consider the mass of the body.
It directly calculates the kinetic energy of the system.
Consider the following statements regarding the inertia force: • It is a real physical force acting on the body. • Its magnitude is equal to the product of the body's mass and acceleration (ma). • It always acts in the same direction as the body's acceleration. • It can also be referred to as the Reversed Effective Force. Which of the above statements are correct?
1 and 3
2 and 4
1, 2, and 3
2, 3, and 4
For a ladder resting against a vertical wall and a horizontal floor to be in static equilibrium, what is the minimum surface condition required?
Both the wall and the floor must be rough.
The wall must be rough, and the floor can be smooth.
At least the floor must be rough.
Both the wall and the floor must be smooth.
In the context of belt friction, the formula T1/T2=eμθ is only valid under which specific condition?
When the belt is moving at a constant velocity.
When the belt has a negligible mass.
When the belt is on the verge of slipping.
When the angle of wrap is less than 90°.
If a body is decelerating (slowing down) while moving to the right, in which direction does the inertia force act?
To the left
To the right
Downwards
Upwards
What is the condition experienced by a person in a lift when the downward acceleration 'a' becomes equal to the acceleration due to gravity 'g'?
The person feels twice their normal weight.
The person's apparent weight becomes zero.
The person's apparent weight is unchanged.
The inertia force becomes zero.
[Conceptual] Why is it stated that T1>T2 in a belt drive system transmitting power?
T1 is the tension on the driving side, which must be greater to overcome the slack side and the load.
T2 experiences more friction from the pulley.
The formula is only valid if T1 is arbitrarily assigned to the larger value.
The weight of the belt adds to T1 but subtracts from T2 .
[Numerical] The angle of friction for a surface is found to be 30∘ . What is the maximum static frictional force (limiting friction) that can be developed if the normal reaction force is 200 N?
100 N
115.47 N
173.2 N
200 N
[Conceptual] According to the Laws of Dry Friction, the magnitude of the friction force is independent of:
The normal reaction force.
The coefficient of friction.
The relative velocity of the surfaces.
The area of contact.
