Mechanics is the branch of Physics that studies the motion of objects and the forces acting upon them. It includes concepts such as displacement, velocity, acceleration, force, work, energy and momentum. This topic forms the foundation of Physics and is frequently asked in UPSC, SSC, Railway, NDA, CDS and other competitive examinations.
Correct Answer:
(D)
Volume
The scalar quantity is defined as the quantity that has only got magnitude, but not directions whereas, vector quantity comprises of both magnitude and directions. Displacement, velocity and force are the examples of vector quantity while volume is a scalar quantity.
Ques: 2
Which one of the following is a scalar quantity?
Correct Answer:
(B) Pressure
Force, velocity and acceleration are the examples of vector quantity while pressure is a scalar quantity. Pressure is defined as the force per unit area. It is the force acting in all direction on an area while force is a pull or push in a specific direction.
Ques: 3
Cycle and cars used ball bearing, because-
Correct Answer:
(C) The effective area of contact between the wheel and axle is reduced.
The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. Due to ball bearing, the effective area of contact between the wheel and axle is reduced and hence, the frictional force also reduced.
Ques: 4
The working principle of a washing machine is:
Correct Answer:
(A) Centrifugation
The working principle of a washing machine is based on centrifugation. Centrifugation is a technique which involves the application of centrifugal force to separate particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed.
Ques: 5
Consider the following statements: A Simple Pendulum is set into oscillation. Then:
The acceleration is zero when the bob passes through the mean position.
In each cycle the bob attains a given velocity twice.
Both acceleration and velocity of the bob are zero when it reaches its extreme position during the oscillation.
The amplitude of oscillation of the simple pendulum decreases with time.
Which of these statements are correct?
Correct Answer:
(C) 1, 2 and 4
When an object, which is in simple periodic motion passes through its mean position then,
No force acts on it.
Its acceleration becomes zero.
Maximum velocity.
Maximum kinetic energy.
Potential energy is zero.