AS Mechanics

Question 1

gravity

Answer 1

force of attraction between all objects

Question 2

inextensible string

Answer 2

a string that does not stretch under load- acceleration is the same in objects connected by a inextensible string

Question 3

light object

Answer 3

mass of the object is small compared to other masses, like a string or pulley (treat objects as having zero mass)

Question 4

smooth surface

Answer 4

assume there is no friction between the surface and any object on it

Question 5

weight

Answer 5

gravitational force that acts vertically downwards

Question 6

friction

Answer 6

a force that opposes the motion between two rough surface

Question 7

normal reaction

Answer 7

the force which acts perpendicular to a surface when an object is in contact with the surface

Question 8

tension

Answer 8

the force acting on an object when it is being pulled along by a string

Question 9

air resistance

Answer 9

opposes motion

Question 10

buoyancy

Answer 10

the upward force on a body that allows it to float or rise

Question 11

vector

Answer 11

a quantity with both magnitude and direction (positive or negative)

Question 12

scalar

Answer 12

a quantity with magnitude only (only positive)

Question 13

velocity

Answer 13

rate of change of displacement

Question 14

Displacement-time graphs

Answer 14

Gradient represents the velocity
Average velocity= displacement from starting point/ time taken
Average speed= total distance travelled/ time taken

Question 15

acceleration

Answer 15

rate of change of velocity

Question 16

Velocity-time graphs

Answer 16

Gradient represents the acceleration

Area under graph represents the distance travelled

Question 17

SUVAT Equations

Answer 17

v= u + at
s= 1/2 (u + v)t
v^2= u^2 + 2as
s= ut + 1/2 at^2
s= vt - 1/2 at^2

Question 18

Force of gravity

Answer 18

It causes all objects to accelerate towards the earth. If you ignore the effects of air resistance, the acceleration is constant. The acceleration does not depend on the mass of the object

Question 19

Acceleration due to gravity

Answer 19

Modelled as g= 9.8 m/s^2

Question 20

Newton’s first law of motion

Answer 20

an object at rest and an object moving with constant velocity will continue in the same state unless acted upon by an unbalanced force

Question 21

resultant force

Answer 21

causes the object to accelerate in the same direction as the resultant force

Question 22

Newton’s second law of motion

Answer 22

the force needed to accelerate a particle is equal to the product of the mass of the particle and the acceleration produced (F=ma)

Question 23

Connected particles

Answer 23

When all parts of the system are moving in the same straight line, the whole system can be treated as a single particle

Question 24

Newton’s third law of motion

Answer 24

for every action there is an equal and opposite reaction