Chapter 9 Forces

Question 1

what is a force

Answer 1

a push or pull that one object exert on another

Question 2

what is the SI unit of force

Answer 2

newton (N)

Question 3

name the contact forces

Answer 3

normal reaction force , friction force , and elastic force

Question 4

name the non-contact forces

Answer 4

gravitational force and magnetic force

Question 5

define gravitational force

Answer 5

it is a pulling force between two objects due to their masses. the more mass an object has , the stronger the force.

Question 5

the greater the ____ the greater the gravitational force

Answer 5

mass

Question 6

as the distance gets further the gravitational force _________

Answer 6

decreases

Question 6

define elastic force

Answer 6

it is a pulling or pushing force found in stretched/ compressed springs and elastic materials such as rubber bands.

Question 6

define normal reaction force

Answer 6

it is a pushing force that occurs when an object is physically in contact with another surface

Question 6

tension acts on the _____ __ _______ where the strings meet the object and is directed _____ ___ ______

Answer 6

point of contact , along the string

Question 7

define weight

Answer 7

it is the amount of gravitational force acting on an object

Question 8

define mass

Answer 8

it is the amount of matter in an object

Question 9

does weight change ?

Answer 9

yes it changes with location

Question 10

SI unit of weight

Answer 10

newton (N)

Question 11

SI unit of mass

Answer 11

kilogram (KG)

Question 11

what do you use to measure weight

Answer 11

spring balance

Question 11

define gravitational field strength

Answer 11

it is defined as the force experienced per unit mass by a small test mass at a point in gravitational field

Question 12

what do you use to measure mass

Answer 12

beam balance

Question 13

how do u find weight

Answer 13

weight = mass x gravitational field strength

Question 14

define pressure

Answer 14

it is defined as the force acting per unit area

Question 14

what is energy

Answer 14

energy is the ability to do work

Question 14

what is the SI unit of pressure

Answer 14

N/m^2 also known as the pascal (Pa)

Question 15

what is the SI unit of energy

Answer 15

joule (J)

Question 16

name common forms of energy

Answer 16

kinetic energy , chemical potential energy , elastic potential energy , gravitational potential energy , thermal energy , and sound energy

Question 17

how do u find gravitational potential energy

Answer 17

GPE = mass x gravity x height

Question 18

how do u find work done

Answer 18

force x distance (m) = work done

Question 19

smaller area of contact = ____ __ _____ ____ ________

Answer 19

able to exert more pressure