Gravitation

Question 1

objects near the surface of Earth will…

Answer 1

fall to the ground
pulled down with a force of 9.8N
accelerate at 9.8ms^-2 downwards

Question 2

Newton’s law of gravitation

Answer 2

• there is a force of attraction between two objects
• size of force is proportional to the product of masses of the objects and inversely proportional to the square of the distance between them

Question 3

gravitation equations

Answer 3

W=mg
F=Gm1m2/r squared
g=Gm/r squared

Question 4

force of m1 on m2 is…

Answer 4

the same as m2 on m1

Question 5

force between objects is bigger if…

Answer 5

objects have more mass/ are close together

Question 6

force between objects is smaller if…

Answer 6

objects are far away from each other/ have less mass

Question 7

gravitational field strength of a planet/ satellite depends only on…

Answer 7

its mass and radius

Question 8

where is r measured from?

Answer 8

the centre of the object

Question 9

terminal velocity

Answer 9

constant velocity (zero acceleration) because the upward force (air resistance) is equal and opposite to the weight

Question 10

how high a projectile travels depends on…

Answer 10

vertical velocity

Question 11

how far a projectile travels depends on…

Answer 11

horizontal velocity

Question 12

describe motion of projectile if fired at a large angle

Answer 12

will travel high but not far

Question 13

describe motion of projectile if fired at a small angle

Answer 13

will travel far but not high

Question 14

if ball is accelerating vertically, what never changes?

Answer 14

horizontal velocity

Question 15

what value should never be used in projectile motion questions

Answer 15

the diagonal velocity

must work out h and v components

Question 16

how to lay out projectile questions

Answer 16

SUVAT down side with vertical column and horizontal column

Question 17

what is vertical time equal to?

Answer 17

horizontal time (same object)

Question 18

if from rest, what is u?

Answer 18

0m/s

Question 19

motion equations

Answer 19

v=u+at
v squared=u squared + 2as
s=ut+1/2at squared
s=1/2(u+v)t

Question 20

equation to use for horizontal

Answer 20

s=vt since it is not accelerating

Question 21

what is vertical acceleration

Answer 21

-9.8m/s squared

Question 22

vertical velocity at max height

Answer 22

0m/s

Question 23

what is resultant velocity?

Answer 23

vertical and horizontal velocity added in vector triangle

Question 24

what should always be stated if question asks for velocity?

Answer 24

direction

Question 25

if a projectile is moving horizontally, what is vertical velocity?

Answer 25

0m/s

Question 26

what is final vertical velocity if projectile takes off and lands on a level surface

Answer 26

equal and opposite to the initial vertical velocity