Motion

Question 1

Speed Distance Time

Answer 1

V=d/t

Rearranged to
t=d/v
D=vt

Question 2

Average Speed

Answer 2

Average speed = total distance travelled/total time taken

Question 3

Instantaneous speed

Answer 3

Instantaneous speed = length of card/time taken to break beam

Question 4

Acceleration

Answer 4

Ms-2

A=v-u/t

Acceleration = final speed - initial speed/time

Rearranged to
T=v-u/a
v=u+at
u=v-at

Question 5

Speed time graphs

Answer 5

Distance travelled = area a + area b + area c - etc

Acceleration is the gradient of the line

Question 6

Weight

Answer 6

W = mg

Weight=mass x gravitational field strength

Rearranged to
M=w/g
G=w/m

Question 7

Newton’s second law

Answer 7

F=ma

Force=mass x acceleration

Question 8

Balanced and unbalanced forces

Answer 8

To find them take the smaller one away from the larger one

Question 9

Newton’s first law

Answer 9

When no forced or balanced forces act on an object it remains at rest or continues on at steady speed in a straight line

Question 10

Newton’s third law

Answer 10

If object a exerts a force on object b then object b exerts an equal but opposite force on object a

Action force and reaction force

Question 11

Work done

Answer 11

Ew=fd

Word done = force x distance

Measure of the energy transferred during an energy transformation

Work done has the symbol Ew and is measured in joules

If a constant force is applied over a particular distance, a certain amount of energy is required this is called work done

Question 12

Power

Answer 12

Power is the rate at which energy is transformed during an energy transformation

Power has the symbol p and is measured in watts

P=e/t

Power = energy/time

Question 13

Gravitational potential energy

Answer 13

Ep=mgh

Gravitational potential energy= mass x gravitational field strength x height

Question 14

Kinetic Energy

Answer 14

Ek=1/2mv(2)

Kinetic energy = 1/2 x mass x velocity(2)

Question 15

what is weight

Answer 15

the weight of an object is the force on it due to the earths gravitational pull.

mass remains constant no matter where the object is in the universe but weight depends on the planet

measured in newton’s

Question 16

what is gravitational field strength

Answer 16

the gravitational field strength (g) is the force exerted per unit of mass of an object.

measured in Nkg-1

Question 17

what is a force

Answer 17

forces can change the shape, speed and direction of motion of an object

measured in newton’s N

Question 18

balanced forces

Answer 18

when equal forces act in opposite directions they are called balanced forces

equivalent to no forces

see newton’s first law

Question 19

unbalanced forces

Answer 19

when unbalanced forces act in an object the object changes speed or direction. the acceleration due to an unbalanced force depended on the mass of the object

calculated using newton’s second law

Question 20

what is work done

Answer 20

work done is the measure of the energy transferred during an energy transformation

work done has the symbol Ew and is measured in joules J

Question 21

what is power

Answer 21

power is the rate at which energy is transferred during an energy transformation.

power has the symbol P and is measure in watts W

Question 22

what is gravitational potential energy

Answer 22

the change in gravitational potential energy or Ep of an object is the work done against gravity (lifting) or by gravity (falling)

gravitational potential energy is measured in joules J

Question 23

what is kinetic energy

Answer 23

kinetic energy (Ek) is the energy of an object due to motion.

measured in joules J

the kinetic energy increases as the mass and or speed increases

Question 24

what is the conservation of energy

Answer 24

during any energy transfer the total amount of energy stays the same.

this principle allows numerical problems involving different forms of energy to be solved