Physical Science Ch. 2

Select all the cases in which an object undergoes acceleration. - A car drives uphill at constant speed - The Moon orbits the Earth - An asteroid tumbles through space, far from other objects - A car brakes and slows down - A leaf falls from a tree

- The Moon orbits the Earth - A car brakes and slows down - A leaf falls from a tree

The acceleration of gravity ___________. (select all that apply) A. slows objects that are thrown upward B. is a constant acceleration C. depends on the initial velocity of the moving object D. is about 9.8 m/s² E. is indicated by g

- is about 9.8 m/s² - is indicated by g

Net force ______. (Select all that apply.) - is the overall effect of all the forces acting on an object - is always larger than the individual forces acting on an object - can be larger or smaller than each individual force, depending on the directions they are acting in - is the sum of all the forces acting on an object except gravity

- is the overall effect of all the forces acting on an object - can be larger or smaller than each individual force, depending on the directions they are acting in

A car accelerates along a straight road, which is 15 km long. The car reaches a speed of 75 km/h in 10s. The average acceleration of the car is... A. 2.1 m/s² B. 7.5 m/s² C. 1.5 m/s² D. 5.0 m/s²

2.1 m/s²

You move forward as you walk because ______. A. the ground exerts a force on you B. you exert a force on the ground

A. the ground exerts a force on you

An astronaut (with equipment) has a mass of 125 kg on Earth. On the moon (g=1.67 m/s²), her mass and weight would be... A. 125 kg and 1225 N. B. 125 kg and 209 N. C. 21 kg and 209 N. D. 125 kg and 125 N.

B. 125 kg and 209 N.

The mass of a 100 N sack of seed is closest to ________. A. 10 kg B. 10 lb C. 98 kg D. 1,000 kg

A. 10 kg

A bowling ball of mass 7 kg is dropped from the top of a tall building. It safely lands on the ground 2.0 seconds later. Neglecting air friction, the height of the building is... A. 20 m B. 24 m C. 15 m D. 29 m

A. 20 m

Which of the following statements describes a free fall on Earth? A. An object is falling toward Earth and only gravity is considered as air resistance is ignored. B. The force of gravity is ignored because another force is more dominant. C. An object is dropped in a mine or underground shaft so that atmospheric processes can be ignored. D. An equal and opposite force balances gravity, leaving air resistance as the only effective force on a falling object.

A. An object is falling toward Earth and only gravity is considered as air resistance is ignored.

Aside from air resistance, the most important factor in determining the velocity of a falling object is _______. (Assume the object is falling on Earth.) A. how much time it spends falling B. how strong the force of gravity on it is C. how massive it is

A. How much time it spends falling

Which of the following statements describes a free fall on Earth? A. An object is falling toward Earth and only gravity is considered as air resistance is ignored. B. The force of gravity is ignored because another force is more dominant. C. An equal and opposite force balances gravity, leaving air resistance as the only effective force on a falling object. D. An object is dropped in a mine or underground shaft so that atmospheric processes can be ignored.

A. an object is falling toward Earth and only gravity is considered as air resistance is ignored.

From the equation w=mg, it is apparent that weight is a(n)... A. force B. mass C. acceleration D. none of the answers are correct

A. force

The tendency of a moving object to remain in unchanging motion in the absence of an unbalanced force is called... A. inertia B. free fall C. acceleration D. impulse

A. inertia

What causes the total (net) momentum of a group of objects to change? A. The action of an outside force B. The breakup of an object into many pieces C. Collisions between the objects

A. the action of an outside force

For a freely falling object dropped from rest, the distance it falls is proportional to ____________. A. the square of the time spent falling B. the inverse of the time spent falling C. the inverse square of the time spent falling D. the time spent falling

A. the square of the time spent falling

Newton's third law of motion

Any force exerted on an object from something else is paired with an equal and opposite force exerted by the object on something else.

A student walks across campus from the residence hall to the science lab in 10 minutes. The science lab is 0.2 km from the residence hall. The student's average speed is.... A. 0.2 km/hr B. 1.2 km/hr C. 2.0 km/hr D. 50 km/hr

B. 1.2 km/hr

A 250 g ball travels at a velocity of 40 m/s. Its momentum is _________. A. 4 kg x m/s B. 10 kg x m/s C. 160 kg x m/s D. 10,000 kg x m/s

B. 10 kg x m/s

Satellites in Earth's orbit are constantly falling, but they don't fall to the surface because ______________. A. the solar wind pushes them B. Earth's surface keeps dropping away C. they are propelled by rockets

B. Earth's surface keeps dropping away.

In the absence of any forces, what keeps an object moving at constant speed? A. Gravity B. Inertia C. Momentum D. Mass

B. Inertia

"Whenever two objects interact, the force exerted on one object is equal in size and opposite in direction to the force exerted on the other object." This is a statement of ______ of motion. A. Newton's second law B. Newton's third law C. Newton's first law

B. Newton's third law

In the most basic analysis, motion of an object is inferred by measuring ______. A. its inertia B. a change in its position over a period of time C. a change in its speed

B. a change in its position over a period of time

A heavy object and a light are dropped from rest at the same time on a planet with no air (vacuum). The heavier object will reach the ground... A. before the lighter object B. at the same time as the lighter object C. after the lighter object D. it depends on the shape of the object

B. at the same time as the lighter object

True or false: If we consider an object falling in a vacuum, such as a meteor falling to impact the Moon, there is only a single force involved. A. True B. False

B. false

Galileo was more successful than Aristotle in correctly understanding the nature of force and inertia because ______________. A. he had the benefit of the telescope and based his results on motion from astronomical observations B. he performed more rigorous and logical experiments C. he had access to more kinds of mathematics

B. he performed more rigorous and logical experiments

If an unbalanced force applied to an object doubles, then... A. its velocity doubles. B. its acceleration doubles. C. its acceleration is cut in half. D. its acceleration increases by a factor of four.

B. its acceleration doubles

The speed of light in space is 3.00 x 10⁸ m/s. The time for light from the Sun to reach Earth is 8 minutes and 20 seconds. Therefore, the distance from the Sun to Earth is... A. 2.40 x 10⁹ m B. 8.64 x 10¹² m C. 1.50 x 10¹¹ m D. 2.25 x 10⁹ m

C. 1.50 x 10¹¹

The weight of a 50 kg box is closest to __________. A. 5 N B. 50 N C. 500 N D. 5000 N

C. 500 N

In the most basic analysis, motion of an object is inferred by measuring ____________. A. a change in its speed B. its inertia C. a change in its position over a period of time

C. A change in its position over a period of time

What factors are needed to clearly define the motion of a space shuttle? A. shape of the space shuttle B. mass of the space shuttle C. Distance the shuttle travels & the time it takes to travel to its final destination in space D. All of the above

C. Distance the shuttle travels & the time it takes to travel to its final destination in space

A student gives a book an initial push across the floor. The book slides to stop. Why did the book stop moving? A. The student stopped pushing it. B. The inertia of the book stopped it. C. Friction between the book and the floor stopped it. D. The force of gravity stopped it.

C. Friction between the book and the floor stopped it.

A student is riding a bicycle at a constant speed on a level surface. Compare the force produced by the pedals and the resistive forces of drag and friction. A. The pedal force is greater than the resistive forces. B. The pedal force is less than the resistive forces C. The pedal force is the same as the resistive forces D. No pedal force is required to maintain constant speed

C. The pedal force is the same as the resistive forces.

The ratio of change in velocity to time elapsed is ______. A. speed B. velocity C. acceleration

C. acceleration

The ratio of change in velocity to time elapsed is _____________. A. speed B. velocity C. acceleration

C. acceleration

Everything that happens in the universe can be traced to interactions of... A. matter and gravity B. light and matter C. four fundamental forces D. gravity waves and light

C. four fundamental forces

For a freely falling object dropped from rest, the distance it falls is proportional to _______. A. the inverse square of the time spent falling B. the time spent falling C. the square of the time spent falling D. the inverse of the time spent falling

C. the square of the time spent falling

Speed is equal to ___________. A. direction of motion divided by time B. distance traveled times time taken C. final velocity minus initial velocity D. distance traveled divided by time taken

D. Distance traveled divided by time taken

Which two fundamental forces are we most familiar with through everyday experience? A. Strong and gravitational B. Strong and gravitational C. Strong and weak D. Gravitational and electromagnetic E. Weak and electromagnetic

D. Gravitational and electromagnetic

A basketball is shot at the goal, ignoring drag, which of the following is true? A. both the horizontal & vertical speeds are constant B. both the horizontal & vertical speeds are changing C. The horizontal speed is changing, but the vertical speed is constant. D. The vertical speed is changing, but the horizontal speed is constant

D. The vertical speed is changing but the horizontal speed is constant

In Newton's second law, force has a relationship with which two variables? A. g B. momentum C. velocity D. acceleration E. mass

D. acceleration E. mass

Gravity is an attractive force between... A. all massive objects B. Earth and objects on Earth C. Earth and Moon, and objects on Earth D. all objects everywhere

D. all objects everywhere

Speed is equal to ______. A. direction of motion divided by time. B. distance traveled times time taken. C. final velocity minus initial velocity D. distance traveled divided by time taken.

D. distance traveled divided by time taken.

The newton is a unit of ___________. A. motion B. energy C. power D. force

D. force

The tendency of a body at rest to remain at rest and of a body moving in a straight line to remain moving in a straight line is defined as ______. A. Newton's first law of motion B. Newton's first law C. mass D. inertia

D. inertia

Ignoring air resistance, the velocity of a falling object. A. is constant B. increases for a while, then becomes constant C. depends on the mass of the object D. is constantly increasing

D. is constantly increasing

Which of the following is NOT an appropriate unit of measurement for speed? A. cm/s B. km/h C. ft/year D. kg/s E. miles/month

D. kg/s

If the velocity of an object is decreasing, we say it has a ______ acceleration. A. reverse B. positive C. limited D. negative

D. negative

If you double the mass of an object while an unbalanced force remains constant.... A. the object moves at half the speed B. the acceleration of the object is doubled C. the object will gradually slow down D. the acceleration of the object is halved.

D. the acceleration of the object is halved.

In calculating the centripetal force of an object, what happens to the force when the radius is doubled? A. The force quadruples. B. The force is cut by four. C. The force also doubles. D. The force is cut in half.

D. the force is cut in half.

Which of the following is an example of Newton's 3rd Law of Motion? A. A baseball is hit for a grand slam home run. B. Two cars involved in a head on collision C. Space shuttles blast off from the launch pad D. Sitting at your desk studying physical science. E. All of the above are examples.

E. All of the above are examples

True or False: A car traveling at 20 mph on a curved exit ramp has a constant velocity.

False

True or False: Astronauts experience a weightless condition when they are in orbit.

False

True or False: Newton's second law states that if an unbalanced force acts on an object, it will move at constant velocity

False

True or False: The attractive force a 70 kg person exerts on Earth is much, much smaller than the force Earth exerts on the person.

False

True or False: The force of gravity near the surface of Earth is 9.8 m/s².

False

True or False: The reason a moving object slows down is that its force of motion gradually runs out.

False

True or False: When you roll a ball across the floor, it comes to a stop because you are no longer exerting a force on it.

False

Position unit of measurement

Meters

Speed unit of measurement

Miles per hour (mph)

The idea that a force exists between two bodies and depends on the product of their masses and the square of the distance between them is _______________'s universal law of ________________.

Newton's universal law of gravitation

The idea that a force exist between two bodies and depends on the product of their masses and the square of the distance between them is _________ universal law of ___________.

Newton's; gravitation

Newton's first law of motion

Objects remain in a state of rest or a state of motion unless acted on by an unbalanced force.

Newton's second law of motion

The acceleration of an object is proportional to the force applied and inversely proportional to the mass of the object.

True or False: An object accelerates when it slows or its direction of movement changes.

True

True or False: The momentum of an object remains the same unless an unbalanced force acts on it.

True

_______________ is the speed and direction of a moving object, such as 10 km/h to the west.

Velocity

Impulse

a change in momentum

velocity

a change in postition

acceleration

a change in velocity

momentum

a quantity involving the inertia and velocity of an object

The rate of change of velocity per unit time is _______________.

acceleration

A(n) ___________ is any push or pull on an object.

force

The impulse (change in momentum) an object experiences is greater when the ______ and ______ are greater.

force applied to the object; time of application

What are the four fundamental forces?

gravitational, electromagnetic, strong nuclear, weak nuclear

We describe an object in free fall with consideration to _______________ but not to air _______________.

gravity, resistance

A change in the momentum of an object caused by exerting a force on it for a period of time t is called a(n) ____________.

impulse

Centriprical force

it acts toward the center of the orbit

Centrifugal force

it appears to act toward the outside of the orbit

Mass unit of measurement

kilograms

Velocity unit of measurement

m/s to the north

Acceleration unit of measurement

m/s²

To determine acceleration due to gravity g, you need to know both an object's weight and its _________.

mass

To determine acceleration due to gravity, you need to know both an object's weight and its ___________.

mass

_____________ is a measurement of how much inertia an object has. It is also a measurement of how much matter is in something.

mass

Saying that something is decelerating also means that is has _____________ acceleration.

negative

If an object is acted on by many forces, the resulting acceleration will be the same as if there is one ______________ force, which is the sum of all the forces.

net

A geosynchronous satellite has a(n) ____________ of one day.

period

Weight unit of measurement(s)

pounds or newtons

The distance covered in a specific amount of time is better known as ____________.

speed

The distance covered in a specific amount of time is better known as _____________.

speed

Change in the motion of an object is an acceleration. Such a change will result in a different ______ or ______ or both. -speed -mass -direction -force

speed, direction

Velocity is the __________ and ___________ of a moving object.

speed, direction

You will change the motion of an object if you change its ____________. (Answers could vary)

speed, velocity, or direction

Velocity is the ___________ and ___________ of a moving object.

speed; direction

inertia

the resistance of an object to motion

Select the properties or quantities that you must measure to establish that something is moving. (Choose all that apply.) -acceleration of gravity -mass -time -position

time, position

______________ is the speed and direction of a moving object, such as 10 km/h to the west.

velocity

Newton's law of inertia states that a moving body maintains a constant ____________ unless a ___________ acts on it.

velocity, force

Newton's law of inertia states that a moving body maintains a constant _________ unless a __________ acts on it.

velocity; force

Momentum (p) is the product of an object's ______ and ______.

velocity; mass