Motion, forces and energy

Question 1

Formula: Average speed (ms^-1) (m/s)

Answer 1

distance(m) / time(s)

Question 2

Formula: Average velocity (ms-1) (m/s)

Answer 2

displacement(m) / time (s)

Question 3

Period of a pendulum (s)

Answer 3

total time(s) / no. of swings

Question 4

Acceleration (ms^-2) (m/s^2)

Answer 4

( final - inital velocity(m/s) ) / time(s)

Question 5

Weight (N)

Answer 5

Mass(kg) * Gravitational field strength (g)

Question 6

Force (N)

Answer 6

Mass(kg) * Acceleration (ms^-2)

Question 7

Density (kgm^-3) (kg/m^3)

Answer 7

Mass(kg) / Volume(m^3)

Question 8

Hooke’s law in an equation

Answer 8

Force(N) = Consnat (Nm^-1) * Extension(m)
Force(N) ∝ Extension(m)

Question 9

State Hooke’s law in words

Answer 9

The extension of a spring and the load applied to it are directly proportional until the limit of proportionality is exceeded

Question 10

Describe, qualitatively, the motion in a circular path
due to a force perpendicular to the motion as
(a) speed increases if force _____ , with mass
and radius constant
(b) radius decreases if force _____ , with mass
and speed constant
(c) an increased mass requires an _____ force
to keep speed and radius constant

Answer 10

(a) speed increases if force increases, with mass
and radius constant
(b) radius decreases if force increases, with mass
and speed constant
(c) an increased mass requires an increased force
to keep speed and radius constant

Question 11

Describe solid friction

Answer 11

The force between two
surfaces that may impede motion and produce
heating

Question 12

Describe the moment of a force

Answer 12

A measure of the force’s turning effect

Question 13

Pressure(Pa)

Answer 13

Force(N) / Area(m^2)

Question 14

Fluid pressure(Pa)

Answer 14

Density(kg/m^3) * Gravitantionl field strength(ms^-2 or Nkg^-1) * Height(m)

Question 15

Work(J)

Answer 15

Force(N) * Distance moved(m)

Question 16

Power(W)

Answer 16

Work(J) / Time(s)

Question 17

Kinetic energy(J)

Answer 17

1/2 * Mass(kg) * Velocity^2(m/s)

Question 18

Gravitational potential energy

Answer 18

Mass(kg) * Gravitational field strength(m/s^2) * Height(m)

Question 19

Efficiency (%) of power

Answer 19

[Useful power output(W)/Total power input(W)] * 100

Question 20

Efficiency (%) of energy

Answer 20

[Useful energy output(W)/Total energy input(W)] * 100

Question 21

Moment(Nm)

Answer 21

Force(N) * Perpendicular distance from pivot(m)

Question 22

Force(N) relating to momentum

Answer 22

Change in momentum(kgm/s) / Time(s)

Question 23

Momentum

Answer 23

Force(N) * Velocity(m/s)

Question 24

Impulse(kgm/s or Ns)

Answer 24

Final momentum(kgm/s) - Inital momentum(kgm/s)

Question 25

Centripetal force(N)

Answer 25

[Mass(k) * Velocity^2(m/s)] / Radius(m)

Question 26

Orbital period(s)

Answer 26

[2π * Radius(m)] / Velocity(m/s)

Question 27

Change in gravitational potential energy

Answer 27

Mass(kg) * Gravitational field strength(m/s^2 or N/kg) * Change in height(m)

Question 28

Power in terms of energy

Answer 28

Change in energy(J) / Time(s)