Explore topic-wise InterviewSolutions in .

Oscillatory motion : 

In oscillatory motion, body swings back and forth.

e.g. Motion of a swing, motion of pendulum of a clock.

Linear motion :

In linear motion, an object shows displacement in a straight line, 

e.g. A train in motion, motion of marching soldiers.

Vibrating diaphragm of tabla, drum, dhol and strings of sitar, guitar show oscillatory motions.

1. Non-linear 

2. Uniform 

3. Oscillatory 

4. Periodic 

5. Random.

If an object like a vehicle, moves in a line in such a way that every point of the object moves through the same distance in the same time, then the motion of the object is called translatory motion. 

Example : 

The motion of an apple falling from a tree, the motion of a man walking on a road, the motion of a box when pushed from one comer of a room to the other, are all the translatory motion.

(a) A person walking in a compartment of a stationary train is in motion relative to the compartment and is in motion relative to the platform. 

(b) A person sitting in a compartment of a moving train is at rest  relative to the other person sitting by his side and is in motion relative to the platform.

The different types of motion are : 

1. Translatory motion 

2. Rotatory motion 

3. Oscillatory motion 

4. Vibratory motion 

5. Periodic motion 

6. Multiple motion 

7. Random motion.

Rest and motion are the relative terms because they depend on the observer’s frame of reference. If an observer is at rest in his or her own frame of reference, but he may be moving in other observer's frame of reference. So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body.

(a) Two boys cycling on the road with the same speed are at rest relative to each other. 

(b) The motion in a straight line is rectilinear motion. 

(c) One to and fro motion of a clock pendulum takes time = 2 s 

(d) 36 km h^-1 = 10 m s^-1 

(e) Total distance travelled = average speed × total time taken. 

(f) The weight of a girl is 36 kgf. Her mass will be 36 kg. 

(g) The weight of a body is measured using a spring balance.

S.I. unit of retardation is m/s² .

A freely falling body has non-uniform motion because it covers smaller distances in the initial ‘1 second’ intervals and larger distances in the later ‘1 second’ intervals, i.e., it covers unequal distances in equal intervals of time.

Uniformly accelerated motion

SI unit of retardation is m/s²

A freely falling body has a non-uniform motion because in the initial 1 second the distance covered is small and in the later 1 second the distance covered is large. As the distance covered is uneven, the motion is non-uniform.

a) Vector and scalar

b) Velocity 

c) Acceleration, second, velocity, 3m/s 

d) Displacement, m/s 

e) Velocity, m/s²

(a) vector, scalar

(b) velocity

(c) acceleration, second, velocity, 3m/s

(d) displacement, m/s

(e) velocity, m/s²

The correct answer b) speed

The correct answer c) km/s

The correct answer b) s/m

Two examples of vector quantities are: 

• Velocity 
• acceleration 

Since in both the cases both the magnitude as well as the direction plays a role in assessing its true value.

Quantities having both magnitude and direction are called vector quatities. 

eg: Displacement, Acceleration.

Initial velocity of a stone, u = 5 ms^-1.

Final velocity of a stone v = 0 (at rest)

If the acceleration of the stone during its motion is = -10ms^-2.

Let the maximum height be ‘s’

v = u + at

0 = 5 + (-10)t

t = \(\frac{-5}{10}\) = 0.5s

time taken by stone = 0.5s

As per 3rd Law of motion

v² = u² + 2as

(0)² = (5)² + 2(-10)s

∴ S = \(\frac{5^2}{20}=\frac{25}{20}\) = 1.25 m

Height attained by the store = 1.25 m.

True 

Mechanics is a branch of physics that deals with motion of non – living objects. 

The motion of animals is locomotion and the laws of mechanics cannot be applied to it. Locomotion is a complex phenomenon of movement of different body parts and transition from one place to another.

Correct option is A) m

Correct option is B) 2.5 m/s

B) Always greater than 1

Correct option is D) A or C

D) above all

Correct option is D) π/4

Option : (d) random

(a) Linear motion :

An object that shows displacement along a straight line is called linear motion, 

e.g. A vehicle moving on a road.

(b) Oscillatory motion :

The motion of a body swinging back and forth is called oscillatory motion, 

e.g. Motion of a pendulum of a clock.

(c) Circular motion :

The motion of an object along a circular path is called circular motion, 

e.g. Motion of a ceiling fan.

(d) Random motion :

The motion that changes its direction and speed continuously is called random motion, 

e.g. Motion of a butterfly.

(e) Periodic motion :

The repetitive motion in which the moving object passes through a certain point again and again after a fixed period is called as periodic motion, 

e.g. The minute hand of a clock.

Both the stone and the eraser have reached the surface of the Earth almost at the same time in the absence of air medium (vacuum). But in air medium, due to friction, air offers resistance to the motion of free falling objects. The eraser reaches the first, the sheet of paper reaches later. The air resistance exerted on the sheet of paper is much higher than that of the eraser. The paper crumpled into a ball reaches ground first and plain sheet of paper reaches later, although they have equal mass. The air resistance offer to the plain sheet of paper is much higher than that offered to the paper ball. This is because the magnitude of air resistance depends on the area of objects exposed to air

1. AB + BC 

ABC = 4m + 3m=7m 

AC = 5 m 

2. AB + BC + CD

ABCD = 4m + 3m + 4m = 11m 

ACD = AC + CD = 5m + 4m = 9m 

AD = 3 m 

The shortest distance to reach D from A will be AD, that is 3 m.

(a) Motion of the Earth around the Sun

1. (c) If assertion is true but reason is false.

2. (d) If assertion is false but reason is true.

3. (a) If both assertion and reason are true and reason is the correct explanation of assertion.

(a) constant

(b) zero, 90 km/h

1. (D) 

2. (C) 

3. (A)

 4. (B)

Mass 

It is the quantity of matter contained in a body. Its S.J. unit is kilogram (kg) It is constant for a body and it does not change by changing the place of the body. It is measured by a beam balance.

Weight 

It is the force with which the earth attracts the body. Its S.I. unit is newton (N) and other unit is kilogram-force (kg f) where 1 kg f= 1  ON(nearly). It is not constant for a body, but it changes from place to place. It is measured by a spring balance.