PHY 104- Test 1

Which statement is NOT testable by science?
a. Bacteria acquire resistance to antibiotics through changes in their DNA.
b. People born under the sign of Sagittarius are twice as likely to be teachers as anyone else.
c. Hurricane Katrina was an act of God.
d. There will be a solar eclipse nextTuesday at 11 a.m.

A fact in science is ______.
a. an educated guess
b. a synthesis of well-tested ideas
c. an agreement between trained investigators
d. forever true

Technology is a tool for ______.
a. applying scientific discoveries
b. making the measurements of science
c. extending truth
d. solving social problems

What is the net force on a crate sliding at an unchanging speed when pushed with a steady force of 75 N?
a. Somewhat less than 75 N
b. Zero
c. Slightly more than 75 N
d. 75 N

Newton said that something was needed to change the motion of an object. A clear reading of his first law tells us that what is needed is ______.
a. a non-zero net force
b. a net force
c. no force at all
d. a force

The scientific method of Galileo and Bacon is ______.
a. one of many ways of making discoveries
b. the method of choice for most discoveries
c. today outmoded
d. worthy of memorizing

What is the net force when a pair of 5-N forces simultaneously act in the same direction on an object?
What is the net force when a pair of 5-N forces simultaneously act in the same direction on an object?
a. 5 N
b. 10 N
c. 0 N
d. 7.5 N

Which of Newton’s laws does the equilibrium rule illustrate?
Which of Newton’s laws does the equilibrium rule illustrate?
a. Newton’s third law
b. Newton’s first law
c. Newton’s law of gravity
d. Newton’s second law

Galileo’s definition of speed was a breakthrough because he is acknowledged to be the first to consider ______.
a. distance covered
b. direction
c. time
d. mathematics

The difference between speed and velocity involves ______.
a. the magnitude of each.
b. direction
c. acceleration.
d. path length

If an object moves with constant acceleration, its velocity must…
a. always decrease.
b. be constant also.
c. change by varying amounts depending on its speed.
d. change by the same amount each second.

A car accelerates at 2 meters/s/s. Assuming the car starts from rest, how far will it travel in 10 s?
a. 40 m
b. 2 m
c. 200 m
d. 10 m
e. 100 m

While a car travels around a circular track at a constant speed, its

a. velocity is zero.
b. inertia is zero.
c. acceleration is zero.
d. none of the above

What is the acceleration of the ball when it is moving up, when it is at the maximum height, and when it is moving down? (Note: The acceleration graph is shown in red.)

a. It is always positive.
b. It is always zero.
c. The acceleration is positive when the ball is moving up, zero at the top, and negative when the ball is moving down.
d. The acceleration is negative when the ball is moving up, zero at the top, and positive when the ball is moving down.
e. It is always negative.

A speedometer normally measures ______.

a. distance traveled
b. velocity
c. average speed
d. instantaneous speed

Galileo discovered that when air resistance can be neglected, all objects fall with the same ______.

a. speed
b. energy of motion.
c. acceleration
d. distance

When we are talking about how quickly “how fast” changes, we’re talking about ______.

a. the difference between
b. speed and velocity.
c. free-fall physics
d. increases in falling distance.
e. acceleration

An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration is

a. 0 m/s2.
b. 8 m/s2.
c. 24 m/s2.
d. 5 m/s2.

A rock dropped from a 5-m height accelerates at 10 m/s2 and strikes the ground 1 s later. If the rock is dropped from a height of 2.5 m, its acceleration of fall is

a. twice.
b. half.
c. four times as much.
d. the same.

At one instant a heavy object in air is moving upward at 50 meters per second. One second later its speed is approximately

a. 60 m/s.
b. 50 m/s.
c. 55 m/s.
d. 40 m/s.

An apple falls from a tree and hits the ground 5 meters below with a speed of about

a. 15 m/s.
b. 10 m/s.
c. 20 m/s.
d. 5 m/s.
e. not enough information

Neglecting air resistance, a ball projected straight upward so it remains in the air for 10 seconds needs an initial speed of

a. 110 m/s.
b. 50 m/s.
c. 100 m/s.
d. 60 m/s.
e. 80 m/s.

Which depends on gravity?

a. Mass
b. Weight.
c. Force.
d. Acceleration.

As a skydiver gains speed in falling through the air, air resistance _______.

a. cancels weight.
b. increases.
c. decreases.
d. becomes negligible when terminal speed is reached.

A crate sits at rest on a factory floor. Friction between the crate and floor occurs _______.

a. when the crate is pushed horizontally, whether sliding or not.
b. even when no pushing occurs.
c. only if the crate is sliding.
d. only if the crate is pushed vertically as well as horizontally

The unit of mass is the kilogram, and the unit of weight is the _______.

a. Newton.
b. kilogram also.
c. m/s2
d. metric mass

In considering proportions, acceleration is _______.

a. equal to the product of force and mass.
b. inversely proportional to mass squared.
c. inversely proportional to mass.
d. directly proportional to mass.

A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car?

a. 1000 kg
b. 3000 kg
c. 500 kg
d. 1500 kg
e. none of these

A Volkswagen Bug and a Volvo truck have a head-on collision. Which statement is true??

a. The greater force acts on the Volvo truck.
b. Both forces are identical.
c. The magnitudes of both forces are the same.
d. The greater force acts on the Volkswagen Bug.

A 7-N vector at an angle of 45° to the horizontal has a vertical component that is about _______.

a. 3.5 N.
b. 7 N.
c. 5 N.
d. 0 N

Force vector components for a sled pulled at an upward angle _______.

a. add up to 90°
b. are normally at right
angles to each other
c. add up to 180°
d. are always opposite each other

In the apple-pulling-the orange sequence in this chapter, what is the force that accelerates the system across the floor?

a. Friction between the apple and the floor.
b. The resistance to motion by the orange
c. The backward pull by the orange
d. Internal forces.

When Monkey Mo dangles by a rope and pulls on his cage, each at different angle from the vertical, the rope tension will be greater than _______.

a. the pull on his cage
b. his weight
c. both his weight and the pull on his cage
d. The answer cannot be determined.

A pair of toy freight cars, one twice the mass of the other, fly apart when a compressed spring that joins them is released. Acceleration will be greater for the

a. lighter car.
b. heavier car.
c. same on each.

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

a. 4 m.
b. 3 m.
c. 6 m.
d. 0 m.

When two vehicles collide, momentum is conserved _______.

a. if the collision is inelastic.
b. whether the collision is elastic or inelastic.
c. only if deformation of either vehicle does not occur.
d. if the collision is elastic

A boxer rides with the punch so as to reduce _______.

a. speed
b. impulse
c. force
d. momentum

Momentum is….

A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun

a. because both velocity and momentum are conserved.
b. if the mass of the bullet equals the mass of the gun.
c. because velocity is conserved.
d. because momentum is conserved.
e. none of these

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is

a. less than the force applied to the cement block.
b. more than the force applied to the block.
c. zero.
d. identical to the force applied to the block.
e. impossible to predict without additional information.

A 5-kg shark swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the shark after this meal is

a. 1/5 m/s.
b. 2/3 m/s.
c. 3/2 m/s.
d. 1/6 m/s.
e. 1/2 m/s.

A 2-kg rifle that is suspended by strings fires a 0.01-kg bullet at 200 m/s. The recoil velocity of the rifle is about

a. 0.1 m/s.
b. 1 m/s.
c. 0.001 m/s.
d. 0.01 m/s.
e. none of these

When one does twice the work in twice the time, the power expended is _______.

a. three times as much
b. twice as much.
c. the same.
d. four times as much

When you use kinetic energy it is
a. doubled
b. squared
c. the same

When traveling twice as fast your kinetic energy is increased _______.

a. not at all.
b. by four.
c. by three.
d. by two.

Predict how the upward force exerted on the feet by the scale will compare to the weight of the man if the elevator is moving upward at a constant speed.

a. The upward force on the feet will be equal to the man’s weight.
b. The upward force on the feet will exceed the man’s weight.
c. The upward force on the feet will be less than the man’s weight.

A 1-kg rock is suspended from the tip of a meter stick at the 0-cm mark so that the meter stick balances like a seesaw when the fulcrum is at the 25-cm mark. From this information, what is the mass of the meter stick?

a. 1/4 kg
b. 3/4 kg
c. 1 kg
d. 1/2 kg
e. more than 1 kg

Which will roll down an incline in the shortest time, a can filled with water or the same can filled with ice?

a. ice
b. water
c. both the same
d. Not enough information is given.

Isaac Newton synthesized _______.

a. the pulls of the Moon and the Earth
b. the extent to which gravity extends in the universe
c. terrestrial and cosmic laws
d. the pulls of the planets on one another

What happens to the force of attraction between two planets when the masses of both are doubled?

a. The force quadruples.
b. The force remains the same.
c. The force doubles.
d. The force increases by 16.

One’s weightlessness in space has most to do with _______.

a. no gravity
b. rotational effects
c. one’s mass
d. no support force

When the distance between two stars decreases by half, the force between them

a. decreases by one-half.
b. decreases by one-quarter.
c. stays the same.
d. increases to twice as much.
e. increases to four times as much.

The horizontal and vertical components of velocity for a projectile are _______.

a. independent of each other
b. dependent on each other
c. parts of a parabola
d. equal for angles greater than 45°

A projectile is launched at 30° above ground level. What other angle at the same speed will result in the same range?

a. 60°
b. 15°
c. 45°
d. any angle at 60° or greater

For an Earth satellite in circular orbit, list all the values that do not change.

a. Speed only
b. Speed and gravitational force only
c. Only speed, gravitational force, and distance from Earth
d. Speed, gravitational force, and distance from the Sun and Earth

For an Earth satellite in an elliptical orbit, list all the values that do change.

a. Speed, gravitational force, and distance from Earth
b. Speed
c. Speed, gravitational force, and distance from the Sun and Earth
d. Speed and gravitational force

The foci of the elliptical path for an Earth satellite are _______.

a. one at Earth’s center and the other elsewhere
b. one atop the other at Earth’s center
c. both outside Earth
d. both inside Earth

The Moon does not crash into Earth because

a. Moon has a sufficient tangential speed.
b. Earth’s gravitational field is relatively weak at the Moon.
c. gravitational pull of other planets keeps the Moon up.
d. Moon has less mass than Earth.
e. none of the above

An element is distinct because of its number of

a. electrons.
b. the total mass of all the particles.
c. neutrons.
d. protons.
e. none of the above

Which of the following is NOT a compound?

a. air
b. ammonia
c. water
d. salt
e. all are compounds

What type of force holds atoms together in a crystal?

a. Electromagnetic
b. Magnetic
c. Gravitational
d. Electric

When a tree branch is bent, the region in the center of the branch is the __________.

a. tensile layer
b. elastic layer
c. compressed layer
d. neutral layer