Physics Exam

air resistance

a special type of frictional force that acts upon objects as they travel through the air

independent variable

a variable (often denoted by x ) whose variation does not depend on that of another. changes

dependent variable

a variable (often denoted by y ) whose value depends on that of another.

longitudinal wave

a wave in which the particles of the medium vibrate parallel to the direction of wave motion

If all forces are equal, than the net force will equal...

0

how much is required to keep a 3-kg object moving to the right at a constant speed of 6.0 m/s?

0 N

Example for units and conversions: If the radius of the moon is approximately 1730000 m, what will it be in kilometers?

1,730 km

Object A: a 2 kg object moving at 2 m/s object b: a 4 kg object moving at 4 m/s Object A has _____ momentum compared to object b

1/4 as much

an object is accelerating at a rate of 4 m/s squared when it suddenly has its mass increased by the factor 2. The new acceleration will be...

2 m/s squared

The force of gravity of objects on the moon is approximately one sixth of their value on earth. Joe weighs 600 N on earth. Joes mass on the moon will be approximately

60 kg

Alec has a mass of 62 kg. What is Alec's weight on earth?

620 N

transversal wave

A wave that moves up and down

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Newton's Third Law

For every action there is an equal and opposite reaction

Newton's Second Law

Force equals mass times acceleration

work

Force exerted on an object that causes it to move

Amplitude

Height of a wave

Crest

Highest point of a wave

frequency units

Hz

In a biology experiment the number of yeast cells in a sample is determined by count after 24 hours of growth at different temperatures- identify the Independent and dependent variables in this experiment

IV: different temp, manipulated or changed by experimenter DV: number of yeast cells, relies on different temps

What property of an object describes its natural tendency to resist acceleration?

Inertia

When a catching a baseball bare-handed, a person will draw their hand backwards in the direction of the ball's motion. The act of drawing the hand backwards is much safer than catching the ball with stiff arms. What affect does this have upon the collision of the ball and the hand?

It causes the time of the collision to be greater and the force to be less

energy units

Joules (J)

work unit

Joules (J)

Units and conversions

King Henry died by drinking Chocolate milk- kilo, hecto, deca, b- (meter, liter, gram), deci, centi, milli

Trough

Lowest point of a wave

Mac and Tosh are arguing in the cafeteria. Mac says that if he flings the Jell-O with a greater speed it will have a greater inertia. Tosh argues that inertia does not depend upon speed, but rather upon mass. Who do you agree with?

Mac

which of the following quantities describes an object's tendency to resist a change in its state of motion?

Mass of an object

What's the difference between mass and weight of an object?

Mass refers to the amount of stuff an object possesses and weight is the force of gravity

Impulse units

N x s

during an egg throwing demonstration, a student threw one egg at a concrete wall, and threw another egg at a hanging bed sheet. The egg that hit the wall exploded on impact, while the egg that hit the sheet landed on the ground, unbroken. Which egg experienced the greater impulse? (hint= impulse=f*t)

Same impulse (both have the same mass, and both came to stop)

Which experiences greater acceleration in a car crash, a butterfly or truck?

The butterfly, it has less mass so it will experience a greater acceleration

net force

The combination of all forces acting on an object

Wavelength

The distance between two corresponding parts of a wave

a large truck traveling at 40 mph down lake avenue collides with a monarch butterfly that is crossing the road. How do forces acting upon these two objects compare to one another?

The experience the same amount of force

Which object has the least inertia?

The one with the least amount of mass

is momentum scalar or vector?

Vector, it has magnitude and direction

power unit

Watts (W)

a rightward object is slowing down. Which of the following statements correctly describes the forces acting upon the object A. the leftward force is stronger than the rightward b. the rightward force is stronger than the leftward c. the rightward force is equal in strength to the leftward

a

which has more inertia: a car or bus?

a bus because it has more mass compared to the car. The car will have a greater acceleration though.

weight

a field force due to gravitational attraction between 2 objects (generally earth and an object)

Applied force

a force that is applied to an object by a person or another object

the following statements were made about a 5-kilogram object. which of the following is true? a. the object weighs 50 N b. the object has a mass of 50 kg c. the force of gravity on the object is 9.8 N

a. the object weighs 50 N

a powerful machine is a machine that...

can do work very quickly

impulse

change in momentum

true or false: faster moving objects have a greater kinetic energy

false, mass is also a factor

Wave speed

frequency x wavelength ( v = f λ ) in m/s

Accuracy

how close a measurement or attempt is to the actual or true value

Precision

how consistent results are regardless of proximity to actual target

How can a student determine if there is a net force or not?

if oppositely-directed forces are unequal, then there must be a net force

Explain the relationship between mass and momentum

increase in mass= increase in momentum INVERSES!!

the reason padded dashboards are used in cars is that they

increase the time of impact in a collision

Which of the following can be explained using Newton's first law of motion?

it explains why a moving object keeps the same velocity

Which of the following can be explained using Newton's second law of motion?

it explains why an object accelerates with a particular acceleration value

what is always true about an object with potential energy?

it's above ground

an object is moving horizontally and slowing down. What is true about it's potential energy?

it's constant

How can a small object have such a large momentum? Like a bullet, for example

its going really fast

an apple falls through the air (just before it hits Newton's head.) Disregard air resistance

just the force of gravity is acting since there is no air resistance.

When all individual forces acting on an object are balanced, it is the natural tendency of an object to _____.

keep its velocity constant (either at a zero or non-zero value)

momentum unit

kg m/s

What is the SI unit for mass?

kilogram

unit for acceleration

m/s^2

what factors does kinetic energy depend on?

mass and speed

the momentum of an object depends upon...

mass and velocity

fg=

mass x gravity (10)

amplitude units

meters

wavelength unit

meters

an object with kinetic energy is an object that's...

moving

in order to have momentum, an object must be...

moving!

a leftward force acts on an object moving to the left. is the force doing positive or negative work?

positive

period units

seconds

Energy

the ability to do work

the mass of an object is decreased. What affect does this have on the acceleration of an object?

the acceleration is increased

the net force of an object is increased. What affect does this have on the acceleration of an object?

the acceleration is increased

Normal Force

the contact force exerted by a surface on an object

friction

the contact force that acts to oppose sliding motion between surfaces

Momentum

the force or speed with which something moves

Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?

the large track

SI system of measurement

the modern form of the metric system, and is the most widely used system of measurement.

which of the following is known for certain to be true of an object that is at rest?

the object is experiencing a balance of forces

the individual forces acting upon an object are balanced. One can one infer about the object's motion?

the object isn't accelerating

A sled slides down the hill and reaches the bottom where it gradually slows to a stop. The fact that the sled ultimately stops is best explained by

the presence of an unbalanced force

tension

the pull exerted by a string, rope, or cable when attached to a body and pulled taut

Power

the rate at which work is done

in order to catch a ball, a baseball player moves his or her hand backwards in the direction of the balls motion. During this reduces the force if impact on the player's hand principally because

the time of impact is increased

which egg experienced greater force of impact?

the wall- time to stop decreases, so force increases

why did the egg that hit the sheet not break?

time to stop increased, so force decreased

True or false, an object would have a different weight on Earth than it would have on the moon

true

slope formula

y2-y1/x2-x1