Quizzes > Sc4eng Quiz0 03

UNIVERSITY OF SOUTH AUSTRALIA Applied Physics - School of Electrical & Information Engineering SCIENCE for ENGINEERS QUIZ 0 [ week X ] Time: 20 minutes

Name .....................................................................................

QUESTIONS ( 12 MARKS )

Marks: Zero

ANSWERS

1. Which of the following is the longest? A. B. C. D.

103 m 1,000,000 cm, 1 x 109 µ, 100 nm.

2. The prefix micro represents … A. B. C. D. E.

1/100, 1/1000, 1/10,000, 1/100,000 1/1,000,000.

3. A health conscious fizix student on a bicycle travels 12 km in 40 minutes. The average speed of the student is … A. B. C. D.

0.3 km/hr, 8 km/hr, 18 km/hr, 48 km/hr.

4. A stone is thrown upwards from a roof at the same time as another identical stone is dropped from the roof. The two stones will … A. reach the ground at the same time, B. have the same speed when they reach the ground, C. have the same acceleration when they reach the ground, D. none of the above is correct.

5. The weight of an object.. A. B. C. D.

is the quantity of matter it contains, refers to its inertia, is basically the same quantity as mass but expressed in different units, is the force with which it is attracted to the earth.

6. When a 1 N force acts on an object that has a mass of 1 kg and is able to move freely, the object receives … A. B. C. D.

a speed of 1 ms-1, a velocity of 0.102 ms-2, an acceleration of 1 ms-2, an acceleration of 9.8 ms-2.

7. Which of the following is NOT a real force? A. B. C. D.

an inertial force, a frictional force, a centrifugal force, a centripetal force.

8. When the velocity of a moving object is doubled, its … A. B. C. D.

acceleration is doubled, momentum is doubled, kinetic energy is doubled, potential energy is doubled.

9. An elastic collision conserves … A. B. C.

kinetic energy but not momentum, momentum but not kinetic energy, both momentum and kinetic energy,

D.

neither momentum or kinetic energy.

10. The centripetal force needed to keep the space shuttle in orbit around the earth is provided by … A. B. C. D.

constantly rotating the shuttle, booster rockets, the gravitational force between the moon and the earth, the gravitational force between the shuttle and the earth.

11. Any excess charge on a conductor in electrostatic equilibrium .... A. B. C.

is evenly distributed throughout its volume, is contained entirely within the conductor, resides entirely on its surface.

12. As an airplane starts from rest and then accelerates down the runway towards you, the speed of the sound waves coming towards you will be: A. lower than the normal speed of sound in air, B. equal to the normal speed of sound in air, C. some constant factor greater than the normal speed of sound in air, D. continually increasing.

QUESTIONS &/OR PROBLEMS ( 8 MARKS ) Problem 1 (2 marks) The gravitational force acting on a pigmy hippo is given by F=ma where m is the mass of the hippo and the acceleration, a, will be the acceleration due to gravity, g. The unit of force is newtons, N. What are the dimensions of force? ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… ………………………………………..…………………………………………………………………………… Problem 2 (6 marks) If a crate of cargo is released from an aircraft during horizontal flight and its parachute does not open, how high was the aircraft flying if the cargo crate hits the ground 16 seconds after it was released? Show all of your calculation and draw a diagram to illustrate this situation. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………