Force and Motion

Question 1

(Formula of motion)

v = ?

Answer 1

v = u + at

Question 2

(Formula of motion)

s = ? (no V)

Answer 2

s = ut + ½ at²

Question 3

(Formula of motion)

s = ? (no a)

Answer 3

s = ½ (u+v)t

Question 4

(Formula of motion)

v² = ?

Answer 4

v² = u² + 2as

Question 5

(Formula of motion)

Sn = ?

Answer 5

Sn = Vi + a/2 (2n-1)

Question 6

(Formula of motion)

What is the sign of g when downward motion vs upward motion

Answer 6

Downward: g
Upward: -g

Question 7

Newtons First Law

Answer 7

Body will continue to be at rest when no external force acts upon it

Question 8

Newtons Second Law

Answer 8

Force produces acceleration in direction of force. (a is directly proportional to applied F and inversely proportional to mass)

Question 9

1N = ___ dyne

Answer 9

10^5 dyne

Question 10

Newtons Third Law

Answer 10

For every action there is an equal and opposite reaction

Question 11

Equal and opposite reactions always act on ______. They never _______

Answer 11

Always act on TWO DIFFERENT BODIES . They never CANCEL / NEUTRALIZE THE EFFECT OF FORCE .

Question 12

(Motion of connected bodies)

F1 =
F2 =

Answer 12

F1 = (m1/m1+m2) F

F2 = (m2/m1+m2) F

Question 13

P = mv
SI Unit of P?
Another unit?

Answer 13

SI Unit is kgms^-1

Another unit is Ns

Question 14

Newtons Second Law in terms of momentum

Answer 14

Time rate of change of momentum is equal to the force acting on the body

(F = p/t)

Question 15

Impulse (J) =

Answer 15

J = Ft

Question 16

Elastic collision vs Inelastic collision

Answer 16

Elastic = both momentum and KE is conserved
Inelastic = only momentum is conserved. (KE converted to another form)

Question 17

P1 + P2 = P1’ + P2’

Answer 17

m1u1 + m2u2 = m1v1 + m2v2

Question 18

Speed of approach = Speed of recession

v1 =
v2 =

Answer 18

v1 = (m1-m2/m1+m2) u1 + (2m/m1+m2) u2

v2 = (2m1/m1+m2) u1 + (m2-m1/m1+m2) u2

Question 19

Case when masses equal (m1 = m2)

Answer 19

EXCHANGE Vs

v1’ = u2 and v2’ = u1

Question 20

Case when equal masses, stationary target (u2 = 0)

Answer 20

v1’ = 0
v2’ = u1

(Incident stops moving after collision and target moves with incident’s velocity)

Question 21

Case when incident heaver than target and target is stationary
(m1&raquo_space; m2) (u2 = 0)

Answer 21

v1 = u1 (Velocity of incident wont change)
v2 = 2u1 (Velocity of target will be twice of incident’s)

Question 22

Case when target heavier than incident and target is stationary
(m1 &laquo_space;m2) (u2 = 0)

Answer 22

v1 = —u1 (Incident gets pushed back in opposite direction but same velocity)
v2 = 0 (Target remains stationary)

Question 23

Path of projectile motion is dependent on 2 things:

Answer 23

— Initial velocity (u)
— Forces

Question 24

(Projectile motion)
Velocity at an instant
Vx = ?
Vy = ?

Answer 24

Vx = Vcosø
Vy = Vsinø - gt

Question 25

(Projectile motion)
Position at an instant
Sx = ?
Sy = ?

Answer 25

Sx = ucosøt
Sy = usinøt - ½gt²

Question 26

(Projectile motion)
Height

Answer 26

h = (u² sin² ø / 2g)
(Weird g in height so 2g)
(When 2g then 2 exponents)

Question 27

(Projectile Motion)
Range

Answer 27

x = (u² sin 2ø / g)
(One g in range so 1 exponent)
(but also 2ø)

Question 28

(Projectile Motion)
Time

Answer 28

t = (2u sin ø / g)
(Time = Two)

Question 29

(Projectile Motion)
Max Range
ø = ?º

Answer 29

ø = 45º
R = (v² sin 2(45) / g)
which equals
R = v²/g (because sin 90 = 1)

Question 30

Rmax = ___H
when how many degrees

Answer 30

Rmax = 4H
when 45º

Question 31

R = H when?

Answer 31

tan^-1 (4) = ø = 76º

Question 32

H with respect to T ?

Answer 32

H = gT² / 8
so
T = √(8H/g)

Question 33

When are ø1 and ø2 the same range?

Answer 33

When complimentary angles
ø1 + ø2 = 90

Question 34

(Projectile Motion)
When is a = 0

Answer 34

a = 0 on x axis at all times

Question 35

(Projectile motion)
When is v = 0 ?

Answer 35

v = 0 on y axis at max height

Question 36

(Projectile Motion)
KE H = ?

Answer 36

KE H = ½ mu² cos² ø
or
KE H = KEinitial cos² ø

Question 37

(Projectile Motion)
PE = ?

Answer 37

PE = ½mu² sin² ø

Question 38

(Projectile Motion)
Momentum?

Answer 38

Pu = mucosø

Question 39

(Projectile Motion)
PE H / KE H = ?

Answer 39

PE H / KE H = tan² ø