Motion And Force

Question 1

Displacement

Answer 1

Change in the position of body from its initial position to its final position.

Question 2

Velocity

Answer 2

Rate of change of displacement

Question 3

Acceleration

Answer 3

Rate of change of velocity

Question 4

Newton’s first law of motion

Answer 4

The mass of the object is the quantitative measure of its inertia.

Question 5

Momentum

Answer 5

Product of mass and velocity

Question 6

Impulse

Answer 6

When a large force acts on a body for short interval of time, then the product of force and time is impulse

Question 7

Law of conservation of momentum

Answer 7

The total linear momentum of an isolated system remains constant

Question 8

Elastic collision

Answer 8

A collision in which K.E. of the system is conserved

Question 9

Inelastic collisions

Answer 9

A collision in which K.E. of the system is not conserved

Question 10

Projectile motion

Answer 10

The two dimensional motion under constant acceleration due to gravity and inertia

Question 11

Height of projectile

Answer 11

The maximum distance covered by the projectile

Question 12

Time of flight

Answer 12

The time taken by a body to cover a distance from place of projection to the place where it hits the ground

Question 13

Range of projectile

Answer 13

Maximum distance which a projectile covers in horizontal direction

Question 14

Ballistic flight

Answer 14

Ballistic flight is that in which a projectile is given an initial push and then allowed to move freely due to inertia and under the action of gravity

Question 15

Ballistic missile

Answer 15

An unpowered and unguided missile

Question 16

Ballistic trajectory

Answer 16

The path followed by ballistic missile

Question 17

Uniform velocity

Answer 17

In case of uniform velocity, the body covers equal displacement in equal intervals of time
Both magnitude and direction remains the same

Question 18

Variable velocity

Answer 18

In case of variable velocity body covers unequal displacement in equal intervals of time
The magnitude and direction of velocity or both may change

Question 19

An object is thrown vertically upward. Discuss the sign of acceleration due to gravity, relative to velocity, while the object is in air?

Answer 19

Sign of acceleration due to gravity relative to velocity is negative

Question 20

Can the velocity of an object reverse direction when acceleration is constant? If so give an example.

Answer 20

Yes it can be possible.
When a body is thrown vertically upward it’s velocity goes on decreasing due to gravity and becomes zero at maximum height. After that it will reverse it’s direction of velocity, but the acceleration remains constant during whole flight

Question 21

Explain

V and a are parallel

Answer 21

If the velocity of car is increasing along a straight path then velocity v and acceleration a are parallel

Question 22

Explain

V and a are anti parallel

Answer 22

If the velocity of the car is decreasing along a straight path then velocity v and acceleration a are anti parallel

Question 23

Explain

V and a are mutually perpendicular

Answer 23

When a body moves in a circular path then velocity v and acceleration a are mutually perpendicular

Question 24

Explain

A is zero but v is not zero

Answer 24

When car moves with uniform velocity then a is zero but v is not zero.

Question 25

Explain

V is zero but a is not zero

Answer 25

If car is stopped by applying sudden hard brakes then at that instant the velocity of the car v becomes zero but the acceleration is not zero.

Question 26

Motion with constant velocity is a special case of motion with constant acceleration. is this statement true? Discuss

Answer 26

Yes, it is a true statement
When the body moves with uniform velocity then the change in velocity is zero. So acceleration is zero. It remains zero as far as the body moves with constant velocity. Hence acceleration remains constant throughout the motion of the body

Question 27

At what point does a projectile have it’s minimum speed

Answer 27

At the maximum height

Question 28

At what point does a projectile have it’s maximum speed

Answer 28

At
Point of projection
Place where it hits the ground