PHY 100 Exam 1

A scientific theory is a theory that has been proven to be true. T/F

False

Newton was the first to demonstrate that if two bodies of different weights were dropped from the same height at the same time the heavier body would hit the ground first. T/F

False

Which of the things listed below was not one of the basic elements according to Aristotle? a. Earth b. Air c. Fire d. Water e. Metal

Metal

Which of the items below are not attributed to Sir Isaac Newton? a. Set out the Laws of Motion b. Discovered the Law of Gravity c. Developed a Theory of light d. Developed a Theory of cooling e. Discovered the nature of sound and measured its speed f. All of the above

All of the above

How did Newton measure the speed of sound?

He used a hallway of a known length, to create an echo and measured the time it took for him to hear the echo. He used a water clock similar to the one Galileo used for his gravity experiment- with a pendulum.

The story about the dairy farmer, the cow, and the physicist that you heard in the beginning of the semester was intended to illustrate the point that... a. Physicists make lousy farmers b. If cows get too big they will explode c. If you build a very simply model of a problem that ignores the details, it is still possible to gain a great deal of important insight into the problem. d. If you ignore the details of a problem, it is very difficult to gain any meaningful information about the problem.

If you build a very simply model of a problem that ignores the details, it is still possible to gain a great deal of important insight into the problem.

Newton's First Law states that an object moving in a straight line at constant velocity will continue to do so unless acted upon by an external force. An object at rest is just a special case of an object in motion. Why is this law important?

It defines the a frame of reference under which his other laws will apply.

Who was the first scientist to propose, based on observations, the earth and the planets traveled around the sun rather than the sun and the planets traveled around the earth. a. Sir Isaac Newton b. Galileo c. Nicolaus Copernicus d. JohannesKepler e. None of the above

Nicolaus Copernicus

If I exert a force on an object for several minutes but do not move it, from a physicist's perspective do I do any work? Y/N

No

Which of the following is not an example of Cognitive Bias?

Peer review - I read it in a scientific journal that require peer review before they publish an article so it must be reasonable.

A Watt is the name of a unit of measure applied to which of the items listed below? a. Energy b. Power c. Force d. Torque e. Momentum

Power

In physics a vector is something that has two characteristics associated with it. What are they?

Size and direction

In order for a theory to be considered a scientific theory it must be

Testable

Which of the following was not one of Archimedes' simple machines? a. The wheel b. The pulley c. The lever d. The screw

The Wheel

Two bicycles and their riders weigh exactly the same. Both bicycles have wheels with the same diameter but the wheels on one bicycle are much heavier than the wheels on the other bicycle. Suppose the two bicycles and their riders start to roll down a hill who will get their first? a) The bicycle with the heavier wheels because they have more angular momentum b) The bicycle with the lighter wheels because less of the kinetic energy goes into the motion of the wheels. c) The both get there at the same time.

The bicycle with the lighter wheels because less of the kinetic energy goes into the motion of the wheels.

Aristotle believed that an object fell to the earth because..... a) The body was attracted by gravity. b) The body also contained the materials that made up the earth and like materials attracted each other. c) The Gods pushed the body toward the earth if someone was not holding it. d) None of the above.

The body also contained the materials that made up the earth and like materials attracted each other.

A woman swings a ball attached to a string in a circle over her head. Neglecting gravity for the moment what is the direction of the force on the ball? a. The force is toward the center of the circle made by the swinging ball b. The force points out, away from the center of the circle, so that the ball does not come into the center. c. There is no force because the ball is moving with a uniform speed. d. None of the above.

The force is toward the center of the circle made by the swinging ball

Newton's third law states that for every action (force) exerted on an object there is an equal and opposite reaction (opposite force). If this is true, how do you explain why a cart moves when it is pulled by a horse? After all, if the horse exerts a force on the cart to pull it forward, then the cart must exert and equal and opposite force on the horse. Don't these forces cancel each other?

The forces are indeed equal and opposite but they act on different objects. There is only one force acting on the cart to move it forward. The other force is acting on the horse.

Before a paper can be published in a reputable scientific journal the editors of the journal require which of the following be true?

The paper must be reviewed other scientists working in the same or similar area of study. This is called peer review.

A hockey puck slides along the ice at a practice session before a game. As it slides, it slows down.

The puck will slow down and eventually stop because the most natural state of an object is at rest.

In physics power is defined as which of the following? a. The rate at which work is done b. The ability to move a massive object c. The ability to influence people and events d. Theabilitytodeterminewhetherornotastudent passes a physics course e. All of the above

The rate at which work is done

Angular Momentum is defined as the moment of inertial of an object times its angular velocity. In straight forward terms that do not use the jargon of physics what is angular momentum a) Another name for linear momentum when it goes around a corner. b) The momentum of an object that is bent in to an unusual shape. c) The tendency of an object that is rotating with a constant speed to keep rotating at that speed unless something tries to change its speed. d) None of the above e) All of the above

The tendency of an object that is rotating with a constant speed to keep rotating at that speed unless something tries to change its speed.

In the time of Aristotle and those that were guided by his ideas the scientific process was to observe a series of related phenomena and then draw a conclusion as to why they happened. This process was expanded into the scientific method that we use today by Roger Bacon, Galileo, and Newton. How did they change Aristotle's process? a. They added experimentation to test the conclusion and modified the conclusion based on the results then retested the modified conclusion. b. They used mathematics instead of philosophy to develop their conclusions. c. They stopped believing in the Greek and Roman Gods as the reasons for what they observed. d. None of the above.

They added experimentation to test the conclusion and modified the conclusion based on the results then retested the modified conclusion

In the time of Aristotle and those that were guided by his ideas the scientific process was to observe a phenomenon and then draw a conclusion as to why it happened. This process was expanded into the scientific method that we use today by Roger Bacon, Galileo, and Newton. How did they change Aristotle's process? a. They added experimentation to test the conclusion and modified the conclusion based on the results then retested the modified conclusion. b. They used mathematics instead of philosophy to develop their conclusions. c. They stopped believing in the Greek and Roman Gods as the reasons for what they observed. d. None of the above.

They added experimentation to test the conclusion and modified the conclusion based on the results then retested the modified conclusion.

In which case below will the ball be rolling fastest when it reaches the bottom of the ramp. Assume the ball starts from the same height in each case.

They would be traveling the same speed in each case

If I drop a 10 pound ball off a tall building at the same time that I drop a 100 pound sack of concrete which item will appear to hit the ground first and why? a. The 10 pound ball because it is smaller and therefore offers less air resistance. b. The 100 pound sack of concrete because it is heavier than the ball. c. There is not enough information to predict the result. d. They would both hit the ground at about the same time.

They would both hit the ground at about the same time.

"Angular Acceleration" is a physicist's term for the rate at which a rotating object speeds up or slows down. T/F

True

"Angular Velocity" is a physicist's term for the speed at which something is rotating T/F

True

A Calorie is a unit of measure for energy. T/F

True

Angular momentum is conserved. That is if a rotating body interacts with another rotating body the sum of the angular momenta before they interact is the same as the total sum of their angular momenta afterward. T/F

True

Energy is always conserved. It may change from kinetic energy to potential energy but the total amount is always the same. T/F

True

Galileo proposed that a body at rest is just a special case of a body moving with constant velocity.

True

Galileo proposed that a falling body would gain equal amounts of speed in equal time intervals. T/F

True

Galileo said an object in motion would remain in motion unless acted upon by a force T/F

True

Galileo was able to correctly measure the relationship between time and distance traveled for an accelerating object with remarkable accuracy given the tools of his time. T/F

True

Physicists define the momentum of an object as the product of its mass times its velocity. T/F

True

Power is the rate at which work is done. T/F

True

The momentum of an object will always remain the same unless it is acted on by an external force? T/F

True

Torque is defined as the force I apply to an object in the direction I want it to rotate times the distance between point where I apply the force and the point of rotation T/F

True

When a wheel with a radius R rotates through one full revolution the distance it covers on the ground is equal to the distance around the wheel. T/F

True

I have a boat that weighs 1000 lbs. When I put it in the water it will take up the space occupied by 1500 lbs. of water. Will it float? Y/N

Yes

The momentum of an object will always remain the same unless it is acted on by an external force? Y/N

Yes

A car traveling down a level road at a constant speed goes around a curve to the left. According to Newton's first law as the car goes around the curve is there a force acting on the car? a. No because the car is traveling at a uniform speed on a level surface. b. Yes because it is changing direction. c. None of the above. d. There is not enough information.

Yes because it is changing direction.