motion and force

Question 1

it is impossible if

Answer 1

a body having constant velocity and variable acceleration

Question 2

a body is thrown vertically upwards. if air resistance is taken to be in account then the time during which rises is

Answer 2

less then the time of fall

Question 3

it is correct

Answer 3

a body with zero velocity will not necessarily have zero acceleration

Question 4

it is not correct

Answer 4

-a body having zero velocity necessarily will have zero acceleration
-a body having uniform speed can have only uniform acceleration
-a body having non uniform velocity have zero acc

Question 5

momentum of body can be changed by

Answer 5

force of air resistance if surface area of body is large

Question 6

all moving body possess

Answer 6

momentum but not impulse if they are moving with uniform velocity

Question 7

displacement

Answer 7

The displacement of an object between two points does not tell exactly how the object has actually moved between these points.

Question 8

average speed

Answer 8

-When an object moves with a variable speed, we generally describe its motion in terms of average speed.
-Note that average speed tells us nothing about the different speeds and variations that may have taken place during the journey.

Question 9

average speed

Answer 9

-When an object moves with a variable speed, we generally describe its motion in terms of average speed.
-Note that average speed tells us nothing about the different speeds and variations that may have taken place during the journey.
FORMULA: 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑠𝑝𝑒𝑒𝑑=𝑇𝑜𝑡𝑎𝑙 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑐𝑜𝑣𝑒𝑟𝑒𝑑/𝑇𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛

Question 10

velocity

Answer 10

-The direction of velocity is the same as that of the displacement.
-A body moving with a constant speed in a circle has a variable velocity
-FORMULA: 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =𝐷𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡/𝑇𝑖𝑚𝑒 𝑡𝑎𝑘𝑒𝑛

Question 11

formula

Answer 11

1. t= s/v
   2.

Question 12

Newton’s Law of Motion

Answer 12

Newton’s laws of motion are only applicable if an object moves with a velocity which is negligible compared to the speed of light, which is 3.0 x 108 ms-1

Question 13

Newton’s First Law of Motion (inertia)

Answer 13

-It gives qualitative definition of force
-The inherent property of the body with which it cannot change its state of rest or of uniform motion unless acted upon by an external force, is called inertia. Hence, Newton’s first law of motion may also be called law of inertia.

Question 14

Newton’s Second Law of Motion
( law of acceleration)

Answer 14

-It gives quantitative definition of force.
-When a force is applied on a body an acceleration is produced in the direction of force
and the magnitude of acceleration is directly proportional to the applied force and
inversely proportional to the mass of the body.

𝐹 ⃗= 𝑚𝑎

Question 15

Newton’s Third Law of Motion

Answer 15

-To every action there is an equal and opposite reaction
-action and reaction act on different bodies
-forces in
nature occur in pairs
-Single isolated force is not possible.
-In certain case of electrostatics and in springs Newton’s 3rd law fails.