Newton's Laws And Forces

Question 1

what was Newtons first law

Answer 1

• if the resultant force on a stationary object is zero, the object will remain stationary
• if the resultant force on a moving object is zero, it will continue moving at the same velocity

Question 2

what is the resultant force

Answer 2

the sum of forces acting upon an object

Question 3

if the resultant force on a moving and stationary object is 0, what happens

Answer 3

• the moving object still moves at the same velocity

- the stationary object stays that way

Question 4

what happens if the resultant force on a stationary object is not 0

Answer 4

it will accelerate in the same direction of the force

Question 5

what happens if the resultant force on a moving object is not 0

Answer 5

it will accelerate, decelerate or change direction

Question 6

if a ball is tied to a string and is spun around, what force is acting upon it

Answer 6

centripetal force

Question 7

what is the speed and velocity of a ball that is tied to a string ans spun around

Answer 7

the speed is always the same and the velocity is always changing and therefore accelerating

Question 8

why is the ball tied to a string accelerating when spun around

Answer 8

because the direction is always changing

Question 9

when a bucket of water is tied to a rope and spun around, what force acts upon the bucket

Answer 9

tension force

Question 10

what is a scalar quantity

Answer 10

quantities that are described by a magnitude

Question 11

what is a vector quantity

Answer 11

quantities that are described by a magnitude and a direction

Question 12

what is Newtons second law

Answer 12

• the larger the resultant force acting on an object, the more it accelerates so force and acceleration are directly proportional
• acceleration is inversely proportional to the mass of the object
• f = ma

Question 13

what is acceleration

Answer 13

the increasing change in velocity

Question 14

when do objects accelerate

Answer 14

when the resultant force is not 0. if the resultant force is doubled the acceleration will double too

Question 15

formula for calculating acceleration

Answer 15

a= v-u / t. (end velocity - start velocity)

Question 16

formula for calculating force

Answer 16

f= ma

Question 17

what is inertial mass

Answer 17

the ratio of force over acceleration, or m = f / a

Question 18

What is newton’s third law

Answer 18

when two forces interact, the forces they exert on eachother are equal ad opposite

Question 19

explain why you dont move when you lean on a wall even though you are exerting a force

Answer 19

• when he pushes against the wall, theres a normal contact force acting back on him
• two forces are the same size
• as man applies force and pushes wall, the wall pushes back with equal force

Question 20

explain the interactions of forces when two skaters, skater B being heaver, push against each other

Answer 20

• when skater a pushes skater b, she feels an equal opposite force from skater b’s hand
• this is is the normal contact force
• both skaters feel the same sized force in opposite directions
• the accelerate from eachother
• skater a has a smaller mass, so will accelerate more than skater b. a = f / m

Question 21

when can an object only be in equilibrium

Answer 21

when the weight of it is equal to the normal contact force