Laws of Motion

Question 1

Momentum P =

Answer 1

√2mKE

Question 2

Impulse J =

Answer 2

change in momentum = Fdt

Question 3

Area under Ft gives

Answer 3

impulse

Question 4

Recoil of gun Vr

Answer 4

Vr = -mV/M

Question 5

Speed Vr =

Answer 5

mV/M

Question 6

F in recoil of gun

Answer 6

nmV

Question 7

For a connected system of 2 masses, a =

Answer 7

(m1-m2)g/m1+m2

Question 8

For a connected system of 2 masses, a =

Answer 8

2m1m2g/m1+m2

Question 9

Motion along inclined surface V =

Answer 9

√2gLsinθ L = len of inclined surf
= √2gH

Question 10

Motion along inclined surface, time to reach ground t =

Answer 10

√2L/a = 1/sinθ√2H/g

Question 11

μk <

Answer 11

μs

Question 12

Motion in circular path

Answer 12

Vmax = √(μ(s) rg)

Question 13

W by spring force

Answer 13

Ws = -kx^2/2

Question 14

W by static fric =

Answer 14

0

Question 15

W by kinetic fric =

Answer 15

-μmgS

Question 16

KE =

Answer 16

PV/2

Question 17

Work energy theorem

Answer 17

W = change in KE

Question 18

stopping dist

Answer 18

S = mu^2/2F

Question 19

W against conservative force

Answer 19

ΔPE

Question 20

W by conservative force

Answer 20

-ΔPE

Question 21

W by centripetal force

Answer 21

0

Question 22

1 horsepower =

Answer 22

746W

Question 23

Wt graph gives

Answer 23

P

Question 24

Efficiency η =

Answer 24

(O/P) power/(I/P) power

Question 25

When P = 0, V =

Answer 25

√2Pt/m

Question 26

When P = 0, a =

Answer 26

√P/2mt

Question 27

Elastic collision

Answer 27

Linear mom, KE conserved, bodies regain shape, force must be conservative

Question 28

Inelastic collisoin

Answer 28

L.M conserved, KE not conserved, bodies don’t regain shape, some f may not be conservative

Question 29

Perfectly inelastic collision

Answer 29

LM conserved, KE not conserved, body is well deformed & don’t regain shape, All F is not conservative

Question 30

If coeff of restitution = 0,

Answer 30

perfect inelastic

Question 31

If coeff of restituion = 1

Answer 31

Perfect elastic

Question 32

If coeff btn 0 & 1

Answer 32

partial inelastic

Question 33

For perfect elastic,

Answer 33

V1 = [(m1-m2)u1 + 2m2u2]/m1+m2

Question 34

For perfect inelastic

Answer 34

V = [m1u1 + m2u2]/m1+m2

Question 35

KE loss =

Answer 35

m1m2(u1-u2)^2/2(m1+m2)

Question 36

When u1 & u2 are opp, KE loss =

Answer 36

m1m2(u1+u2)^2/2(m1+m2)

Question 37

r =

Answer 37

(m1r1 + m2r2)/m1+m2

Question 38

Center of mass for cone

Answer 38

Solid cone - h/4
Hollow cone - h/3

Question 39

In explosion in parabolic path

Answer 39

m1r1 = m2r2

Question 40

Shift in trolley in opp dir

Answer 40

x = ml/m+M

Question 41

Radius of gyration K for ring =

Answer 41

MR^2

Question 42

K for disc

Answer 42

MR^2/2

Question 43

K for solid sphere

Answer 43

2/5MR^2

Question 44

K for hollow sphere =

Answer 44

2/3MR^2

Question 45

K for rod

Answer 45

ml^2/12

Question 46

Moment of inertia I =

Answer 46

mr^2

Question 47

Angular momentum L =

Answer 47

Iω

Question 48

Angular impulse

Answer 48

ΔL

Question 49

Rotational power Pr =

Answer 49

τω

Question 50

KE of pure rolling body

Answer 50

1/2mv^2 β

Question 51

V for Rolling motion on an inclined plane

Answer 51

V = √2gH/β

Question 52

a for rolling motion on inclined plane

Answer 52

a = gsinθ/β

Question 53

t for rolling motion on inclined plane

Answer 53

t = 1/sinθ√2hβ/g