PHY1020C Exam 1

If you throw a ball up in the air on the Earth, ignoring air friction, at a velocity 20 m/s, 3 seconds later its velocity is A) -10 m/s B) 0 m/s C) 20 m/s D) 10 m/s

A) -10 m/s

If you push on a wall with 10 N of force and the wall does not move, how hard is the wall pushing on your hands A) 10 N. B) can't be determined. C) less than 10 N. D) greater than 10 N.

A) 10 N.

The velocity of a boat is 12 mi/hr. If it accelerates at a rate of 2mi/hr/min, after 4 minutes its velocity is A) 20 mi/hr B) 16 mi/hr C) 24 mi/hr D) 15 mi/hr

A) 20 mi/hr

Which has the greatest mass? A) a small automobile battery B) all the choices have the same C) an open umbrella D) a king-size pillow

A) a small automobile battery

When you hang from a ring supported by two ropes not directly over the ring, the vector sum of the support forces (tension) on the ropes will always A) add up to your weight. B) each be less than your weight. C) each equal your weight.

A) add up to your weight.

An object in mechanical equilibrium could be A) all three of the other conditions. B) moving with constant velocity. C) having no acceleration. D) at rest.

A) all three of the other conditions.

Eratosthenes learned about the position of the sun on June 22 by A) consulting library information. B) setting up a stick at Alexandria. C) setting up sticks at both Syene and Alexandria. D) setting up a stick at Syene.

A) consulting library information.

When a scientist is dishonest and reports false information, he or she A) gets no second chance in the scientific community. B) like in so many other professions, will be excused by the scientific community.

A) gets no second chance in the scientific community.

In science, an educated guess is a A) hypothesis. B) theory. C) fact D) law

A) hypothesis.

In science, theories A) may change. B) are absolute. C) mean very little. D) are the same as facts.

A) may change.

While a car travels around a circular track at a constant speed, its A) none of the above B) inertia is zero. C) velocity is zero D) acceleration is zero.

A) none of the above

Terminal velocity means that A) objects reach a speed where the upward force of the air molecules equals the downward force of gravity. B) the net force on an object falling through air never changes. C) the acceleration of gravity increases over time until a maximum of about 10 m/s/s is reached. D) objects of different mass falling through air must eventually reach the same downward speed due to air resistance.

A) objects reach a speed where the upward force of the air molecules equals the downward force of gravity.

The safest way for you to view the sun is with A) pinhole images shining on a flat surface. B) a telescope C) binoculars. D) colored sunglasses.

A) pinhole images shining on a flat surface.

Galileo discredited Aristotle's interpretation of motion using A) the acceleration of free fall B) the role of push and pull in describing motion C) the motions of the planets around the sun

A) the acceleration of free fall

The synthesis of a large collection of information that contains well-tested and verified hypotheses about certain aspects of the world is known as a scientific A) theory. B) hypothesis. C) fact D) law or principle.

A) theory.

An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be A) twice as much. B) none of these C) the same. D) four times as much. E) half as much.

A) twice as much.

In science, a personal ideology or set of beliefs is A) useless, because science advances only by observing and testing hypotheses. B) should never be changed no matter what an experiment indicates. C) the same as a fact. D) the foundation for creating hypotheses

A) useless, because science advances only by observing and testing hypotheses.

A car maintains a constant velocity of 60 mi/hr for 1 hour. During this interval its total acceleration is A) zero. B) 1 mi/hr. C) 60 mi/hr. D) 1/60 mi/hr.

A) zero.

When you lift a 50 N barbell and hold it in place over your head, the net force on the barbell is A) 50 N B) 0 C) 100 N total. D) -50 N

B) 0

In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the A) Earth. B) moon. C) planet Jupiter

B) Moon

The two measurements necessary for calculating average speed are A) velocity and time. B) distance and time. C) acceleration and time. D) distance and acceleration E)velocity and distance.

B) distance and time.

The scientific method is most effective in A) discovering new things. B) gaining, organizing, and applying new knowledge. C) performing experiments. D) making theories. E) making hypotheses.

B) gaining, organizing, and applying new knowledge.

If one object has twice as much mass as another object, it also has twice as much A) acceleration due to gravity. B) inertia. C) all of these D) velocity. E) volume.

B) inertia.

A ball rolls down a 30° incline onto a horizontal surface. When it reaches the end of the flat surface, It rolls up a 45° slope until A) it has rolled the same distance up the second incline as it rolled down the first incline. B) it reaches the same height above the flat surface that it started at. C) the acceration it is experiencing equals 0. D) The time it went down the first incline equals the time it travels up the second incline.

B) it reaches the same height above the flat surface that it started at.

When a car drives down the road, the REACTION force that pushes the car FORWARD to overcome the car's inertia (and friction) is supplied by the A) engine. B) road. C) driver. D) tires.

B) road.

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that A) the milk carton has no acceleration. B) the milk carton has inertia. C) gravity tends to hold the milk carton secure. D) there is an action-reaction pair of forces.

B) the milk carton has inertia.

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is A) equal to its weight divided by its mass. B) zero. C) equal to its weight. D) equal to the product of its mass times its weight.

B) zero.

If a baseball is thrown straight up at 7 m/s on the Earth, when it falls its acceleration is A) 7m/s/s. B) 13 m/s/s. C) 10 m/s/s. D) 3 m/s/s.

C) 10 m/s/s.

The drag of air friction on a plane flying at a constant velocity is 1000 N. The force provided by the plane's needed to maintain a constant velocity is 1000 N. A) less than 1000 N B) more than 1000 N C) 1000 N

C) 1000 N

Edgar stands a platform suspended from two ropes. He weighs 1800 N. He is not standing in the middle. The left rope provides 600 N of force to support the platform. The right rope must provide A) It depends where he is standing. B) 600 N C) 1200 N D) 1800 N.

C) 1200 N

A 300kg bear grasping a vertical tree is stationary. The friction force between the tree and the bear is A) 30 N B) more than 3000 N C) 3000 N D) 300 N

C) 3000 N

The acceleration of gravity is 10 m/s/s. If an object free falls for 4 seconds, its velocity is A) 80 m/s B) 20 m/s C) 40 m/s D) More information is needed.

C) 40 m/s

Science is a body of knowledge that A) condenses knowledge into testable laws. B) is an ongoing activity of humans. C) All of the other choices are correct. D) describes order in nature.

C) All of the other choices are correct.

The easiest way for you to measure the distance between the Earth and the moon is to place in your line of sight to the moon a A) compass B) string C) Coin D) a piece of cheese

C) Coin

The scientist to first introduce the concept of inertia was A) Aristotle. B) Copernicus C) Galileo. D) Newton.

C) Galileo.

Between 3 and 4 seconds of fall, the distance a freely falling object on Earth will fall is A) about 80 m B) about 16 m C) about 35 m D) 42 m

C) about 35 m

When you stand at rest on a pair of bathroom scales, the readings on the scales will always A) always be half your weight. B) each equal your entire weight. C) always add up to your total weight.

C) always add up to your total weight.

A ball is thrown upwards and returns to the same position from where it left the thrower's hand. Compared with its original speed immediately after release, its speed when it returns to the same point is about A) half as much B) four times as much C) the same D) twice as much

C) the same

When the moon orbits the Earth, it has velocity. Inertia would make the moon continue in a straight line instead of orbiting at that velocity. The fact that it orbits at the same distance t tells you that A) the force pulling it toward the Earth is less than inertia. B) the force pulling it toward the Earth is greater than inertia. C) there is a constant force equal to inertia pulling it toward the Earth D) Inertia doesn't apply to planets.

C) there is a constant force equal to inertia pulling it toward the Earth

With no air resistance, which falls faster a feather or a bowling ball? A) feather. B) bowling ball. C) they fall the same speed. D) it depends whether there is high gravity or low gravity.

C) they fall the same speed.

A race car travels at a constant speed of 160 mph for 10 seconds. What is the total acceleration over that 10-second interval? A) 1600 mph. B) 160 mph C) 16 mph D) 0

D) 0

Gravitational acceleration on a planet is 1 m/s/s. If basketball star LeBron James can jump 2 meters into the air on this planet, what is his hang time? (Remember, LaTeX: t =\sqrt{2d/g} t = 2 d / g ). A) 4 s. B) .5 s C) 3 s. D) 2 s.

D) 2 s.

If a car increases its velocity from zero to 100 km/h in 20 seconds, its acceleration is A) 80 km/h/s. B) 120 km/h/s. C) 10 km/h/s. D) 5 km/h/s E) 2000 km/h/s.

D) 5 km/h/s

Whereas Aristotle relied on logic in explaining nature, Galileo relied on A) mathematics B) patterns C) logic also D) experiment

D) experiment

A player catches a ball. Consider the action force to be the impact of the ball against the player's glove. The reaction to this force is the A) player's grip on the glove. B) muscular effort in the player's arms. C) none of these D) force the glove exerts on the ball. E) friction of the ground against the player's shoes.

D) force the glove exerts on the ball.

A sack of turnips free-falling through the atmosphere reaches terminal velocity when A) the sack reaches the ground. B) the maximum amount of gravity has been felt by the sack. C) the sack reaches the thickest air. D) the resisting drag force equals the gravitational force. E) ... never! The accelerating force always keeps increasing the velocity of the sack..

D) the resisting drag force equals the gravitational force.

With no air resistance, what is the acceleration of a1000 kg car whose engine produces 250 N of force A) 250,000 N/kg B) 4 m/s^2 C) 1250 N/kg D) 250 m/s^2 E) .25 m/s^2

E) .25 m/s^2

The Newton is a unit of A) force B) inertia C) mass D) density

force

Whenever the net force on an object is zero, its acceleration A) may be more than zero B) zero C) may be less than zero

zero