Conceptual Physics 3rd six weeks test: Chapters 1-8, 12, 21 and 22

Multiple Choice

Identify the choice that best completes the statement or answers the question.

1. A scientific hypothesis is a valid scientific hyphothesis only if there ___

a.	is a way to prove it correct.	c.	is a way to prove it wrong.
b.	are other hypothesis like it that have been proven wrong.	d.	are other hypothesis like it that have been proven correct.

2. Scientific theories constantly change. This is ___

a.	not a good thing because it shows how inaccurate science is.	c.	a good thing becasue initally theories are often always wrong.
b.	not a good thing because it causes a great deal of confusion.	d.	a good thing because it brings us closer and closer to the truth.

3. Religion is about ___, while science is about ___.

a.	cosmic purpose, cosmic order	c.	purpose, order
b.	cosmic order, cosmic purpose	d.	order, purpose

4. The best scientific theories are the ones that ___

a.	answer the most questions.	c.	explain the most things.
b.	raise the most questions.	d.	make the fewest predictions

5. An object falls freely in a vacuum on Earth, as it does so ___

a.	its acceleration remains constant.	c.	its velocity decreases
b.	its velocity remains constant.	d.	acceleration decreases.

6. As an object falling through the air approches its terminal velocity which of these is true:

a.	Its acceleration remains constant.	c.	Its velocity becomes nearly zero.
b.	The distance it covers each second becomes less and less.	d.	The distance it covers each second is greater and greater.

7. Suppose you are driving a car that is going around a curve at a constant speed of 25 miles per hour. Which of these is true:

a.	Your dispalcement is constant because your motion is not in a straight line.	c.	Your velocity is constant because you are not changing speed.
b.	You are accelerating because you are changing direction.	d.	Your speed is changing because you are turning.

8. An object is in free fall if ___

a.	it is falling freely through the air prior to reaching terminal velocity.	c.	it is falling throuhg the air at terminal velocity.
b.	one and only one force acts on an object and that one force is air resistance.	d.	one and only one force acts on an object and that one force is gravity.

9. Note the two vectors below. Which configuration must these vectors be in so that a vector resolution can be calculated?

a.		c.
b.		d.

10. If cannonball 1 is dropped vertically at the same time that cannonball 2 is shot out of the cannon at 30 m/s which cannonball will hit the ground first?

a.	Cannonball 1	c.	both cannonballs will hit the ground at the same time.
b.	Cannonball 2	d.	There is not enough information to answer this question.

11. Note the illustration of “Newton’s Cannon”:

Disregarding air resistance, which cannonball or cannonballs is or are being acted on by gravity and only gravity?

a.	Cannonball ‘A’ only	c.	Cannonball ‘C’ only
b.	Cannonballs ‘A’ and ‘B’ only	d.	Cannonballs ‘A’, ‘B’ and ‘C’

12. The horizontal component of a projectile’s velocity is independent of

a.	the force exerted on the projectile.	c.	the verticle component of the projectile.
b.	the angle at which the projectile is thrown.	d.	the horizontal speed at which it was launched.

13. Note the young man pushing the ten kilogram mass in the grocery cart. If this activity were to take place on the moon, which statement below best describes what happens when the boy turns a corner?

a.	The boy would find turning a corner harder on the moon than on Earth.	c.	The boy would find turning a corner on the moon exactly the same as turning a corner on Earth.
b.	The boy would find turning a corner easier on the moon than on Earth.	d.	The boy would not be able to turn a corner on the moon since there is no gravity on the moon.

14. The lunar rover, pictured below, weighs 2058 N on Earth. Suppose the astronauts found a bolder on the moon with the same weight on the moon. Which object has more mass?

a.	The bolder	c.	Neither, they both have the same mass.
b.	The lunar rover	d.	Neither, objects do not have mass on the moon.

15. An object is in equilibrium when

a.	the sum of all forces acting on the object is zero.	c.	the sum of the horizontal forces is equal to the sum of the vertical forces.
b.	the sum of the downward forces is equal to the sum of the sidways forces.	d.	the net force acting on the object is non-zero.

16. The force requried to maintain an object at constant speed in friction free space is equal to

a.	zero.	c.	the mass of the object.
b.	the inertia of the object.	d.	the force required to stop it.

17. An apple that weighs 1 N, such as the one pictured below, is in free fall. What is the net force on the apple?

a.	0.0 N	c.	1.0 N
b.	0.1 N	d.	908 N

18. When a parachutist. such as the one pictured below, is approching terminal velocity, his velocity is ___ while his acceleration is ___.

a.	decreasing, decreasing	c.	decreasing, increasing
b.	increasing, increasing	d.	increasing, decreasing

19. The combination of all forces acting on an object is called

a.	the balanced force.	c.	the unbalanced force.
b.	the object force.	d.	the net force

20. Note the three objects in free fall pictured below. Although each of these objects have a different mass they all accelerate at the same rate in the absence of air resistance. This is because

a.	their weight to mass ratio, F/m. is the same.	c.	their weight to inertia ratio depends on their acceleration.
b.	the force acting on them is the same.	d.	they all have the same inertia in free fall.

21. According to Newton’s Third Law it is impossible to hit a hanging sheet of tissue paper with a large force because

a.	the tissue paper is largely affected by air resistance.	c.	the tissue paper is nearly weightless and massless.
b.	the tissue paper cannot hit back with a large force.	d.	the tissue paper will easily tear.

22. A rocket is able to accelerate the vacuum of space. The force that accelerates the rocket is the force of

a.	of the vacuum of space pulling on the rocket.	c.	the exhaust gases pushing on the vacuum of space.
b.	of the rocket on the exhaust gases.	d.	the exhaust gases on the rocket.

23. A force is exerted in the tires of a car to accelerate the car along the road. The source of the force that causes this accelerated motion is

a.	the normal force of the road.	c.	the car’s engine.
b.	the friction force of the road.	d.	the car’s tires.

24. Two teams of ten students are involved in a tug-o-war. Each team pulls with a force of 4000 N. What is the tension in the rope?

a.	zero newtons	c.	4000 N
b.	2000 N	d.	8000 N

25. When a student jumps from a table they always bend their knees when they land. By doing this the time it takes the student to stop is increased by at least ten times what it would be with a stiff legged stance. This means the force needed to stop is

a.	reduced to zero.	c.	decreased by a factor of ten times
b.	increased by a factor of ten times.	d.	increased to ten times the student’s weight.

26. The kinetic energy of an object is a function of the object’s

a.	mass and velocity.	c.	weight and velocity.
b.	force adn mass.	d.	force and power.

27. Power is

a.	impulse times time.	c.	the ability to do work.
b.	energy in motion.	d.	the rate at which work is done.

28. The SI unit for power is

a.	the Newton - meter.	c.	the Joule - second.
b.	a Watt.	d.	a Joule.

29. An Earth satellite in elliptical orbit is going

a.	slowest when it is nearest Earth.	c.	fastest when it is farthest from Earth.
b.	fastest when it is nearest Earth.	d.	the same speed all the time.

30. All of the energy of a car comes from the

a.	energy stored in the gasoline.	c.	kinetic energy of the car’s motion.
b.	energy stored in the car’s engine.	d.	energy stored int eh car’s battery.

31. Newton knew that an unbalanced force must be acting on the moon because

a.	the moon is round.	c.	only one side of th emoon faces Earth.
b.	the moon travels at constant velocity.	d.	the moon does not go in a straight line.

32. The moon does not fall into Earth because

a.	the moon has less mass than Earth.	c.	of the moon’s tangential velocity.
b.	the force of gravity between Earth and the moon is too small.	d.	of the gravitational pull of all the other planets on the moon.

33. If the force of gravity between two massive objects is 50 N; what will that force be if the distance between them is increased to five times what it was?

a.	2 N	c.	250 N
b.	5 N	d.	1250 N

34. The equation for calculating Universal Gravitation is

a.		c.
b.		d.

35. What did Newton discover about gravity?

a.	Newton discovered that gravity is universal.	c.	Newton discovered that gravity is always an attractive force.
b.	Newton discovered that gravity existed.	d.	Newton discovered that gravity exists only on Earth.

36. Heat is

a.	the same thing as temperature.	c.	the transfer of energy.
b.	the amount of energy something has.	d.	the same thing as internal energy.

37. A substance can gain or lose energy without changing its temperature

a.	when the substance changes volume.	c.	when it is not under pressure.
b.	when the substance changes phase.	d.	when it is under pressure.

38. If a substance is a good absorber of energy

a.	it is a good emitter of energy.	c.	it has a lot of mass.
b.	it is a poor emitter of energy.	d.	it has a high specific heat.

39. Note the figure:

If the ring is put over a flame what will happen?

a.	The size of the ring will change in proportion to the gap so tha gap will remain the same size.	c.	One side of the gap will get larger while the other side of the gap will get smaller.
b.	The ring will get larger and fill in the gap so the gap will get smaller.	d.	The whole ring will will get larger and thus the gap will get larger as well.

40. A lake cannot freeze until the whole lake is

a.	-4 ⁰C	c.	4 ⁰C
b.	0 ⁰C	d.	32 ⁰C

41. A blanket helps you keep warm because it is a good

a.	radiator.	c.	emitter.
b.	insulator.	d.	absorber.

42. Heat is

a.	the measure of the internal energy of a substance.	c.	the transfer of energy from where it is hot to where it is cold.
b.	the temperature of a substance.	d.	the transfer of internal energy from where it is hot to where it is cold.

43. Note the figure below. Which term best describes how the marshmallows are getting hot?

a. radiation c. conduction

b. convection d. induction

a.	Convection	c.	Conduction
b.	Radiation	d.	Induction

44. According to Newton’s Law of cooling

a.	the greater the temperature difference the greater the rate of energy transfer.	c.	the greater the rate of energy transfer the larger the specific heat of a substance.
b.	the lesser the temperature difference the greater the rate of energy transfer.	d.	objects with low specific heat capacities require more energy to cool.

45. The specific heat of a substance tells you

a.	how much energy it takes to bring it out of equilibrium.	c.	how much energy it takes to bring it into equilibrium.
b.	how much energy it takes to change its internal energy.	d.	how much energy it takes to change its temperature.

46. Note the illustration below:

This is an example of energy being transferred by

a.	radiant cooling	c.	conduction
b.	radient heating	d.	convection

Problem

47. A basketball with a mass of 0.62 kg is thrown so that it has a velocity of 5.0 m/s. What is its momentum?

48. A 55 kg student is riding on his skate brard with a momentum of 242 kgm/s. What is his velocity?

49. A force of 150 N is needed to lift a box 3.5 m. How much work was done?

50. A 0.003 kg bullet is fired at 360 m/s. What is its momentum?