Ambo IBIBS School Physics Mid-term Exam.

Grade 12

Grade 12 Midterm Examination

Subject: Physics
Date: 19/03/2017 E.C
Total Mark: 20%
Time Duration: 1:30:00

Instructions:
 Write your name, class, and section at the top of your answer sheet.
 No calculator or electronic devices are allowed during the exam.
 All answers must be clearly written. Illegible answers will not be marked.
 The exam contains 40 questions, 6 pages (including the cover).
 Read carefully each questions.
 Answer all questions. Time management is crucial.
 Choose the best answer from the given alternatives and write the letter of your choice
on the provided separate answer sheet.

Constants that you may use

 Gravitational acceleration, g = 10 m/s2
 Density of water, ⁄
8
 Speed of light in air (v = 3 × 10 m/s)
 Sin400 = Cos500 = 0.64
 Cos400 = Sin500 = 0.77
√
 sin450 = cos450 =

Prepared by: Desta Negash

Checked by: Dechasa Yadeta

1 November 2017 E.C Good Luck!

Ambo IBIBS School Physics Mid-term Exam. Grade 12

1. Athlete Sifan failed down in the truck. A physicist interprets this phenomenon as:
A. She did not get rest. C. She did not eat food.
B. Her center of mass is outside the base. D. She is overloaded.
2. What physics concept is used to explain the motion of planets around the sun?
A. Newton’s universal gravitation C. Conservation of energy
B. Electromagnetic induction D. Thermodynamics
3. Which of the following physical phenomena is exploited in the CT scan imaging process to
differentiate between tissues?
A. Reflection of X-rays C. Absorption of X-rays
B. Refraction of X-rays D. Diffraction of X-rays
4. An Ethiopian defense force sends a signal to a target. The signal takes 0.01 seconds to return. What is
the distance between the radar and the target in meter?
A. 3 × 106 B. 3 × 1010 C. 1.5 × 106 D. 1.5 × 1010
5. A chemical engineer uses the principle of fluid dynamics to design a reactor with a flow rate of 2 m3/s.
If cross-sectional area of the pipe decreases by half, what will be the new velocity of the fluid assuming
incompressible flow? A. Double B. Halves C. Remain the same D. Quadruples
6. Which of the following is true about the vertical velocity of a projectile in horizontal projection
(ignoring air resistance)?
A. It decreases over time C. It increases over time
B. It remains constant D. It is zero at any point on the path
7. A bullet of 200 mg mass is fired from a 30.0 m high building horizontally. At the same time a bullet of
the same mass fired vertically down from the same height. What can be concluded about the motion of
two bullets?
A. A bullet fired horizontally takes more time to strike the ground
B. Both bullets strike the ground at the same time
C. Both bullets move with the same horizontal velocity.
D. A bullet fired vertically takes more time to strike the time.
8. A ball is projected horizontally from a height of 20 m with a speed of 10 m/s. how long does it take for
the ball to hit the ground? A. 1 s B. 2 s C. 3 s D. 4 s
9. Which of the following statements is correct about components of the velocity of a ball projected up at
an angle of with the horizontal? Neglecting the air resistance,
A. The vertical component of the velocity remains constant throughout its journey.
B. The vertical component of velocity increases while the horizontal component of velocity decreases.
C. The horizontal component of the velocity remains constant throughout its journey.
D. The horizontal velocity of the ball is equal to zero at the maximum height.
10. A bullet is fired with an initial speed V at an angle with the horizontal. It takes a time T to reach
maximum vertical displacement hmax. It hits the target point a distance R away and exactly in the
horizontal level to the point where it was fired. Which one of the following statement is not correct
about motion of the bullet?
A. The bullet hits the target at a time 2T after it fired.
B. hmax is directly proportional to the initial speed v.
C. R will be maximum if √
0
D. should be different from 90 to hit the target at distance R.

2 November 2017 E.C Good Luck!

Ambo IBIBS School Physics Mid-term Exam. Grade 12

11. Figure below shows a trajectory of a projectile projected from the ground. What is the square of the
magnitude of the initial velocity of the projectile in (m2/s2)?

A. 100 B. 400 C. 200 D. 20

12. A projectile is fired from ground level with an initial velocity that has a vertical component of 40 m/s
and a horizontal component of 60 m/s. The distance from launching to landing points is:
A. 960 m B. 480 m C. 240 m D. 800 m
13. You are tasked with designing a new type of projectile system that minimizes the time of flight while
maximizing the horizontal range. Considering that you are operating in an environment where air
resistance plays a significant role, which combination of factors would you optimize?
A. Increase the launch angle and decrease the initial velocity.
B. Increase the launch angle and increase the initial velocity.
C. Decrease the launch angle and increase the initial velocity.
D. Decrease the launch angle and decrease the initial velocity.
14. The angular speed of the minute hand of a watch is
A. 600/minute B. 0.10/minute C. 2π radian/minute D. 60/minute
15. For a rigid body rotating about a fixed axis,
A. For the same time interval, point closer to the axis turn through a smaller angle than a point farther
from the axis
B. For the same time interval, a point closer to the axis and a point farther from the axis travel the
same linear distance.
C. A point closer to the axis has smaller linear speed than a point farther from the axis.
D. The point closer to the axis has larger linear speed than a point farther from the axis.
16. You are on a big wheel of radius at a fairground which makes 1 revolution every 8 seconds. The
operator of the wheel decided to stop the wheel by applying the brakes. The brakes produce an
acceleration of – 0.1 rad/s2. How much linear displacement the wheel covered before it comes to a
stop?

A. 1.25 m B. 2 m C. m D. m

3 November 2017 E.C Good Luck!

Ambo IBIBS School Physics Mid-term Exam. Grade 12

17. Consider the following figure that describes rotation of an object about a fixed axis.

Which one of the following is correct about rotation of the object?

A. The direction of rotation is clockwise.
B. Angular velocity and angular acceleration are parallel to the plane of rotation.
C. The angular velocity of the object is increasing.
D. The angular velocity of the object is decreasing.
18. The angular speed of a disk rotating about its axis increases by 2000 rad/s in a time interval of 3 s. If
the moment inertia of the disk is 0.6 kg.m2, what is the average torque on the disk?
A. 670 Nm B. 1200 Nm C. 6000 Nm D. 400 Nm
19. Three forces act on a bar as shown in Figure below. Calculate the net torque about axis A.
A. 6.60 N.m Counter clock wise C. 2.77 N.m Counter clock wise
B. 3.83 N.m Clock wise D. 8.15 N.m Counter clock wise

20. A ring and a solid disk, both with mass 2 kg and radius 0.5 m, roll down an incline without slipping.
Which reaches the bottom first and why?
A. The ring, because it has greater inertia
B. The disk, because it has lower moment of inertia
C. They reach at the same time because mass is equal
D. It depends on the incline’s angle
21. A disk of radius 0.10 m and mass 0.1 kg is set into motion by a tangential force 2.0 N applied at the
edge of the disk. If the angular acceleration of the disk is 400 rad/s2, the torque and angular velocity at
2.0 s are, respectively;
A. 0.2 N.m and 800 rad/s C. 0.5 N.m and 100 rad/s
B. 0.1 N.m and 200 rad/s D. 0.2 N.m and 400 rad/s
22. By what factor would a person’s weight at the surface of Earth change if Earth had its present mass but
eight times its present volume?
A. 4 B. 8 C. D. ¼
23. The reason why planets don’t fall into the sun from its strong gravitational force is due to:
A. High enough radial acceleration of the planets.
B. Counter repulsion force.
C. Balanced force of repulsion and attraction forces.
D. High enough tangential velocity of the planets.
4 November 2017 E.C Good Luck!
Ambo IBIBS School Physics Mid-term Exam. Grade 12

24. If a planet has an orbital period that is 27 times that of Earth’s, what is the mean distance of the planet
from the sun in astronomical units (AU)?
A. 9 AU B. 27 AU C. 81 AU D. 3 AU
25. Tensile stress is the
A. Parallel component of the applied force divided by the cross-sectional area of an object.
B. Ratio of change in length of an object to the original length.
C. Perpendicular component of the applied force divided the cross-sectional area of an object.
D. Ratio of original to the change in length of the object.
26. An engineer is analyzing two different manometers to measure the pressure difference of a gas in a
tank. One is an open-end manometer using mercury, and the other is a closed-end manometer using
water. Which of the following should be considered to evaluate the accuracy of the pressure
measurements?
A. The density of the fluid used in each manometer. C. The color of the fluid used.
B. The ambient temperature in the room. D. The length of the manometer tubes.
27. A substance with a mass of 2 kg has a volume of 2.5 x 10-3 m3. What is the relative density of the
substance? A. 80 B. 8.0 C. 0.8 D. 1.25
28. If a diver descends to a depth of 20 meters underwater, how does the pressure compare approximately
to the atmospheric pressure (101kpa) at the surface?
A. It is equal to the atmospheric pressure. C. It is twice the atmospheric pressure.
B. It is lower than the atmospheric pressure. D. It is 3 times the atmospheric pressure.
29. Suppose a cylinder diameter 10 cm and length 2 m is fully filled with water, what is the pressure
exerted due to the water column at the base of the cylinder, if the container is open to atmosphere and
the local atmospheric pressure is 101kPa? A. 121kPa B. 321kPa C. 405kPa D. 96kPa
30. You are designing a hydraulic system for lifting heavy objects in a workshop. To maximize the lifting
force while minimizing the input force, which of the following would be the best design decision?
A. Use a small piston on the input side and a larger piston on the output side.
B. Use pistons of equal size on both input and output sides.
C. Use a larger piston on the input side and a smaller piston on the output side.
D. Increase the fluid viscosity in the hydraulic system to increase the output force.
31. A hydraulic system, a small piston with a force of 100 N moves down a distance of 0.2 m. If the large
piston moves up by 0.02 m, what is the force exerted by the large piston?
A. 200 N B. 500 N C. 1000 N D. 2000 N
32. Two connected vessels contain the same fluid, but the cross-sectional area of one vessel is twice that of
the other. When the fluid is in equilibrium, how do the pressure at the same height in both vessels
compare?
A. The pressure is higher in the narrower vessel. C. The pressure is higher in the wider vessel.
B. The pressures are equal. D. The pressure depends on the shape of the vessel.
33. A sealed tank is filled with an ideal fluid, and a hole is made at the bottom. If the tank is suddenly
placed in a vacuum, how will the fluid flow rate through the hole change compared to being in the
atmosphere?
A. The flow rate increases because there is no atmospheric pressure.
B. The flow rate decreases due to lack of external pressure
C. The flow rate remain unchanged
D. The flow rate depends on the shape of the tank.

5 November 2017 E.C Good Luck!

Ambo IBIBS School Physics Mid-term Exam. Grade 12

34. A tall container is filled with two immiscible fluids, oil (density = 800 kg/m3) and water (density =
1000 kg/m3). If a solid object floats at the interface of the two fluids, what can be inferred about the
density of the object?
A. The density is equal to that of water. C. The density is greater than both oil and water.
B. The density is equal to that of oil. D. The density is between the densities of oil and water.
35. An object with a mass of 150 kg and a volume of 0.75 m3 is floating in a liquid of density 0.8 g/cm3.
What percentage of object’s volume will be submerged below the surface of the fluid?
A. 25 % B. 50 % C. 75 % D. 100 %
36. Why does the speed of a fluid increase as it flows through constricted part of a pipe (according to the
continuity equation)?
A. The mass of the fluid decreases C. the volume of the fluid changes
B. The pressure decreases D. The same amount of fluid must pass through smaller area per unit time.
37. Why does airplane experience lift when moving through the air?
A. Air pressure is higher on the top of the wings.
B. Air move faster over the top surface of the wing than below, it creating lower pressure above the wing.
C. The density of the air is greater below the wings than above.
D. Gravity acts less on the air above the wings.
38. Water flows at the rate of 500.0 cm3/s at small cross-section 5 cm2. The larger cross-section is 25 cm2.
What is the ratio of the speed of the water at A1 to A2?

A1 A2
A. 0.2 B. 20 C. 5 D. 100
39. Which of the following factors does not directly affect the flow rate of liquid in a pipe?
A. Cross-sectional area of the pipe C. temperature of the environment outside the pipe
B. Pressure difference across the pipe D. Viscosity of the fluid
40. What is the main characteristics of turbulent flow in a fluid?
A. Smooth and orderly motion. C. Flow only in straight line.
B. Chaotic and irregular motion. D. Zero viscosity.

Answer sheet
Student Name: ____________________________________ Section__________
No Answer No Answer No Answer No Answer
1 11 21 31
2 12 22 32
3 13 23 33
4 14 24 34
5 15 25 35
6 16 26 36
7 17 27 37
8 18 28 38
9 19 29 39
10 20 30 40

6 November 2017 E.C Good Luck!