2. Force, Motion & Gravitation

Question 1

what is mass

Answer 1

measure of amount of matter in the object

Question 2

what is mass measured in

Answer 2

kg

Question 3

does mass change from earth to space

Answer 3

no

Question 4

what is the weight of an objec

Answer 4

defined as the force of gravity on the object and may be calculated as the mass times the acceleration of gravity

Question 5

what is the equation for calculating the weight of a object

Answer 5

w = mg

Question 6

what is the unit for weight

Answer 6

N

Question 7

what is gravity

Answer 7

9.8m/s^2

Question 8

what is the centre of mass

Answer 8

point where all of mass of an object is concentrated

Question 9

what will happen when the object is supported at its centre of mass

Answer 9

it will remain at static equilibrium

Question 10

what is newtons first law

Answer 10

law of inertia

object in state of motion or state of rest will remain in that state unless a net force acts on it

Question 11

what is newtons second law

Answer 11

object is acted upon by a net force, the change in the object state of motion will be inversely proportional to the mass of the object and force acting on the object

Question 12

what is the formula for newtons second law

Answer 12

F = m x a

Question 13

what is newtons third law

Answer 13

for every action there is an equal (in size) and opposite (in direction) reaction

Question 14

what is gravitation

Answer 14

force of attraction existing between any 2 bodies of masses in the universe

Question 15

what is r in the gravitation equation

Answer 15

measured as distance from centre of one mass to centre of other

Question 16

what is the gravitation force equation

Answer 16

F = G((m1 x m2)/r^2)

Question 17

what is G in the gravitation formula

Answer 17

6.673 x 10^-11m^3kg^-1s^-2

Question 18

___ N is the force needed to accelerate one kg of mass at the rate of one m/s^2

Answer 18

1

Question 19

what is free fall motion

Answer 19

vertical motion of an object with reference towards earth

Question 20

what is the kinematic equation for distance (x)

Answer 20

x = x0 + v0t + 1/2at^2

Question 21

in free fall motion what is a equal to

Answer 21

gravity

Question 22

what is the kinematic equation for velocity (v)

Answer 22

v = v0 +at

Question 23

what is the kinematic equation for velocity squared (v^2)

Answer 23

V^2 = v0^2 + 2ax

Question 24

do linear motion equations apply to projectile motion

Answer 24

no as they follow a parabola in terms of motion

Question 25

how do you solve projectile motion questions

Answer 25

1. separate projectile motion into 2 components - x and y
2. calculate linear y component (acceleration = 9.8m/s^2)
3. calculate linear horizontal component (no air resistance so horizontal acceleration = 0)
4. input values into linear motion equations

Question 26

what is the equation for maximum friction

Answer 26

fmax = uN

u = coefficient of friction
N = normal force to surface on which object rests

Question 27

what are the 2 things to remember for friction

Answer 27

a frictional force is always parallel to surface in contact with object

normal force is always perpendicular to the surface in contact with object

Question 28

what are the 2 forces acting on object in inclined planes

Answer 28

force of gravity downwards (weight)

normal force perpendicular to surface of object

Question 29

what equation can be used to determine the perpendicular component of gravity in solving problems for objects down an incline

Answer 29

F1 = m x g x cos

Question 30

what equation can be used to determine the parallel component of gravity in solving problems for objects down an incline

Answer 30

F2 = m x g x sin

Question 31

what is the acceleration of the object on an incline if there is no friction present

Answer 31

parallel component/mass

A = (m x g x sin)/m
A = g x sin

Question 32

what is the centripetal acceleration

Answer 32

particle moving in circular motion at constant speed where the constantly changing direction of the velocity is causing radially inward acceleration

Question 33

what is centripetal acceleration determined by in terms of equations

Answer 33

ac = v^2/r

Question 34

what is the equation for centripetal force

Answer 34

if ac = v^2/r & Fc = m x ac

then

Fc = mv^2/r

Question 35

what is hookes law

Answer 35

F = kx

k = spring constant

Question 36

what is tension

Answer 36

force acting on a flexible object with no mass such as rope or string

Question 37

if there is no friction on the rope what is assume about tension

Answer 37

that it is equal throughout the rope