Physics Exam

31. When a force F is applied to a wire of length L fixed at one end, the wire extends by x. The tensile strain of the wire is

A. the length L divided by the extension x.
B. the extension x divided by the length L.
C. the product of the force F and the extension x.
D. the applied force F divided by the extension.

32. Which one of the following factors does NOT affect the moment of inertia of an object?

A. The size of the object
B. The axis about which the object is rotating
C. The mass of the object
D. The angular speed of the object

33. About an axis of rotation perpendicular to a plane of a couple, the forces in a couple produce

A. non-zero resultant force.
B. no torque.
C. torques in the same direction.
D. torques in opposite direction.

34. Which of the following describes the difference between static and dynamic equilibrium? In static equilibrium,

A. an object moves with constant acceleration, whereas in dynamic equilibrium, the object is at rest.
B. an object is at rest, whereas in dynamic equilibrium, the object moves with constant velocity.
C. an object moves with constant velocity, whereas in dynamic equilibrium, an object is at rest.
D. acceleration is zero, whereas in dynamic equilibrium the acceleration increases uniformly.

35. Which one of the following statements describes the difference between heat and temperature?

A. Heat is measured with a thermometer in Kelvin, whereas temperature is measured with a Calorimeter in Joule.
B. Heat is a transfer of energy due to temperature difference, whereas temperature is a measure of the average kinetic energy.
C. Heat is an energy that flows spontaneously from colder to hotter object, whereas temperature is the degree of hotness and coldness.
D. Heat is a measure of the average kinetic energy, whereas temperature is a flow of energy from hotter to colder object.

36. Which one of the following statements does NOT describe the relationship of physics with biology?

A. Physics and biology used to study how air vibrates in vocal cords.
B. Physics and biology are interrelated to each other in the study of vision and color detection.
C. Newtonian mechanics and biology are used to explain why cheetah is fastest animal.
D. Both physics and biology are mainly concerned in the interaction of large number of particles.

37. Which one of the following is a correct relation of physics with medicine?

A. Medicine is a branch of physics dealing with nuclear reaction.
B. Modern medical imaging instrument are developed with knowledge of medicine and later used by physics.
C. A discipline called medical physics deals with principles of physics in medical diagnosis.
D. Physics is a branch of medicine that sets standards during medical diagnosis.

38. A ball is released from a height h. It then rises to a maximum height of 2h after collision with the ground. Neglecting air resistance, which one of the following statements is correct about the ball's mechanical energy?

A. Mechanical energy of the ball increases while moving downward, but decreases while moving upward.
B. Mechanical energy after collision is less than mechanical energy before collision.
C. Mechanical energy before collision is equal to after collision.
D. Mechanical energy after collision is greater than mechanical energy before collision.

39. A glass tube of radius 30 mm is inserted in a bowl which contains methyl iodide of density 2.28 kg/m³. If the contact angle of the methyl iodide in the tube is 30° and the surface tension is 0.26 N/m, how much height does the methyl iodide rises through the tube?

A. 0.66 m
B. 0.52 m
C. 0.066 m
D. 6.6 m

40. Two rods, one made of brass and the other made of copper, are joined end to end. The length of the brass section is 0.2 m and the length of the copper section is 0.8 m. Each segment has cross-sectional area 0.005 m². The free end of the brass segment is kept at 100°C and the free end of the copper segment is kept at 0°C. If the rate of heat flow is the same through both rods, what is the temperature of a point where the two segments are joined? (kor= 109 W/m·K)

A. 10.2 °C
B. 50 °C
C. 53 °C
D. 100 °C

41. A pressure applied to one point in an enclosed incompressible fluid is transmitted to all parts of the fluid without reducing in value. This is the principle of

A. Bernoulli.
B. Continuity.
C. Pascal.
D. Archimedes.

42. Which of the following statement describes uniform motion?

A. An object, starting from rest, moving on a straight line to attain a velocity of 30 m/s
B. An object moving with constant speed of 30 m/s in a straight line
C. An object moving around a circular track with constant speed of 30 m/s
D. An object moving at 30 m/s toward East and then 30 m/s toward North

43. Which of the following statement describes inertia of an object? It

A. is a physical quantity which has a unit of mass.
B. makes to change state of rest of the object.
C. increases with an increasing velocity of the object.
D. increases with increasing mass of the object.

44. Two objects, object A of mass m and object B of mass 2m are placed at heights of h₁ and h₂, respectively, from the surface of the earth. Assuming that the gravitational field strength is constant, the potential energy of object A is twice of that of object B, if

A. h₁ = 4h₂.
B. h₁ = 1/2 h₂.
C. h₁ = 2h₂.
D. h₁ = 3h₂.

45. A car travels 60 m north and then 80 m west. What is the magnitude of the resultant displacement of the car from its starting point?

A. 4800 m
B. 20 m
C. 140 m
D. 100 m

Physics Exam: Part 3

Exam Results