Thermal Physics Quiz Exam!

Radiation can travel through vacuum;

Conduction take places in solid matter;

Convection takes place in fluid (liquid and gases)

Law of moment states that when moment of anticlockwise rotation is equal to moment of clockwise rotation, the level will experience no rotation and remain in equilibrium form.

Otherwise, the level will undergoes rotation in the direction of the greater moment.



Moment = Force perpendicular to the level x distance from the pivot to the applied force



Clockwise moment

= (1000 N)(1 m)

= 1000 Nm



Anticlockwise moment

= (500 N)(2 m)

= 1000 Nm As



Clockwise rotational moment is equal to anticlockwise rotational moment Hence no rotation occur and the level is under equilibrium state.

Heat will cause the volume of fluid to expand/increase due to the molecules in a matter will vibrate more vigorously and create a larger space in between molecules



as density = mass/volume

then density will decreases when volume increases

Average speed = total distance travelled / total time taken

Total distance travelled

= (2 km/hr)(1 hr) + (5km/h)(2hr) + (6km/hr)(3hr)

= 30 km (change to meter as answer required)

= 30 km x 1000km/m = 30 000 m



Total time taken

= 1 hr + 2 hr + 3 hr

= 6 hr (change to seconds as answer required)

= 6hr x 3600 s/hr = 21600 s



Therefore, Average speed = 30 000 m/ 216 000s = 1.380 m/s

Law of moment states that when moment of clockwise rotation and moment of anticlockwise rotation is equal, then equilibrium is achieved.

Otherwise, the level will follow the direction of moment which having greater value.



Moment = Force perpendicular to the level x distance from the pivot to applied force



Clockwise moment

= (14 N)(2 m) = 28 Nm



Anticlockwise moment

= (5N)(3m +2m) + (6 N)(2m)

= 37 Nm



As the anticlockwise moment is greater than the clockwise moment, Hence, the level will undergoes anticlockwise rotation

Law of moment states that when a level is under equilibrium state, Its clockwise moment is equal to the anticlockwise moment.



Moment= Force perpendicular to the level x the distance from the pivot to the applied force



Clockwise moment = (50 N )(1.4 m) =70 Nm

Anticlockwise moment

= (15 N)(1.4 m + x m) + (15 N )(1 m) + (10 N)(1.5 m + 1 m)

= 21 Nm + 15x Nm + 15 Nm + 25 Nm

= 15x Nm + 61 Nm



In equilibrium state, Clockwise moment = anticlockwise moment

70 = 15x + 61

15x = 9

x =0.6 m

Radiation can travel through vacuum;

Convection usually occur in fluid(gases and liquid);

Conduction take places in solid.



Hence, all types of thermal processes is required for the flame from match reaches thermometer.

Flame emit light which allows heat travelled by radiation reaches the metal bulb of the thermometer,

then the bulb conduct heat and passes the heat to the liquid-in-glass,

Next the liquid-in-glass experience convection and response rapidly toward the changing temperature.

Under free fall assumption, the object is only influence by acceleration due to gravity(9.8 m/s^2)

Hence, It will experience constant acceleration and increasing in speed when time increases.



From the speed-time graph, we can obtain

a) Instantaneous speed from Y-axis of the graph

b) Distance travelled from the area under the graph

c) Instantaneous acceleration from the gradient of graph



From the distance-time graph as well, we can obtain

a) Instantaneous distance travelled from Y-axis of the graph

b) Instantaneous speed from the gradient of the graph

c) Average speed by dividing the Y-axis value with the total time



Therefore, speed-time graph will shows a linear graph with constant gradient 9.8 and the distance-time graph will shows a concave upward graph.