PHSC 1001 Final Exam
Two billiard balls having the same mass and speed roll toward each other. What is the net momentum of the two-ball system?
0 kg*m/s
Two identical freight cars roll without friction towards each other on a level track. One car rolls at 2 m/s and the other car rolls at 1 m/s. After the cars collide, they couple and roll together with a speed of
0.5 m/s
Which has more atoms: a 1-g sample of carbon-12 or a 1-g sample of carbon-13?
1-g sample of Carbon-12 because C12 is lighter than C13
A 1-kg ball is thrown straight up at 10 m/s. Neglecting air resistance, the net force that acts on the ball when it is halfway to the top of its path is
10 N
What is the net force acting on a 1-kg ball in free fall? What is the net force if it encounters 2 N of air resistance?
10 N 8N
A woman who normally weighs 400 N stands on top of a very tall ladder so she is one Earth-radius above Earth's surface. What is her weight there?
100 N
It takes 40J to push a large box 4m across the floor. The force exerted on the crate is
10N
If two protons and two neutrons are removed from the nucleus of an oxygen atom, a nucleus of which element remains?
12/6 C
A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/ s^2. What is the mass of the car?
1500 kg
A car moving at 50 km/h skids 20m with locked brakes. How far will it skid if its initial speed is 150 km/h?
180 m
If an element has 9 protons and 10 neutrons and 9 electrons, which expression correctly identifies the element?
19/9 F
Find the acceleration that can result from a net force of 10 N exerted on a 4-kg cart
2.5 m/s^2
A 1000-kg car accelerates at 2 m/s2. What is the net force exerted on the car?
2000 N
A 1000-kg car accelerates at 2 m/s^2. What is the net force exerted on the car?
2000 N
How many different elements are there in the compound C6H12O6?
3
What is the speed of a 4-kg ball with a momentum of 12 kg*m/s?
3 m/s
Lillian pulls on a 10-kg wagon with a constant force of 30 N. What is the wagons acceleration?
3 m/s^2
A martial arts person breaks a board with a blow of 3000 N. The force that acts on the hand is
3000 N
With no air resistance, a projectile fired at 50 degrees has the same range as if it were fired at
40 degrees
When a 10-kg block is simultaneously pushed toward the east with 20 N and toward the west with 15 N, the combination of these forces on the block is
5 N east
Nellie runs the length of a 100-yard football field in a time of 20 seconds. Her average running speed is
5 yards/sec
Joshua is attracted toward Earth by a 500-N gravitational force. The Earth is attracted toward Joshua with a force of
500 N
Boxes of various masses are on a friction-free, level table. Rank each of the following from greatest to least. Net forces on the boxes. Accelerations of the boxes
5N- 20kg- 15 N, then 5N-5kg-10N = 10 N-10kg-15N = 10N-5kg-15N 5N-5kg-10N = 10N-5kg-15N & 10N-10kg-15N = 5N-20kg-15N
A 5000-kg freight car crashes into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg freight car?
6 m/s
How many atoms are in one molecule of Na2SO4?
7
A boxer punches a sheet of paper in midair from rest to a speed of 40 m/s in .05 s. If the mass of the paper is .01 kg, the force of the punch on the paper is
8 N
Suppose that an object in free fall were somehow equipped with a speedometer. By how much would its speed readings increase with each second of fall?
9.8 m*s^-1
If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element?
98 amu Tc
Starting from rest, Marshall pushes a crate across the floor of his classroom for 3 s with a net force as shown in the net figure below For each crate, rank momenta at the end of 3 s from greatest to least For each crate rank the final speeds from greatest to least For each crate, rank changes in momenta from greatest to least For each crate rank impulses delivered from greatest to least
A (100N, 30 kg), B (75N, 20 kg), C (50N, 10 kg) C, B, A A, B, C A, B, C
Is aging primarily an example of a physical or chemical change?
Aging is an example of a chemical change involving the chemical reformation of our biomolecules.
A ball is released from rest at the left of the metal track shown. Assume it has only enough friction to roll, but not to lessen its speed Rank momenta from greatest to least at each point Rank KEs from greatest to least at each point Rank PEs from greatest to least at each point
C (middle ground or after falling), B and D are equal (on the highest ridges at equal heights), A (point of ball initial fall) C, B=D, A A, B=D, C
Rank the three subatomic particles in order of increasing mass: (a) neutron, (b) proton, (c) electron.
C, B, A Electron, Proton, Neutron
What is the main tenet of Plank's quantum hypothesis?
Energy comes in discrete packets of a certain minimum size
Using the formula for gravity, find the force of gravity on a 1.3 kg mass at Earth's surface.
F = 13 N
Find the force of gravity between Earth and the moon. The average Earth-Moon distance is 3.8 x 10^8 m
F = 2.1 x 10^20 N
To find the force of gravity between the Earth and the Moon. The average Earth-Moon distance is 3.8 x 10^8 m.
F = 2.1 x 10^20 N
If you stand on a frictionless skateboard and push the wall with a force of 50 N, how hard does the wall push on you? If your mass is 90 kg find your acceleration
F = 50 N a = 0.56 m/s^2
Calculate the force of gravity on a 1 kg mass at Earths surface. The mass of Earth is 6 x 10^24 kg, and its radius is 6.4 x 10^6 m Calculate the force of gravity on the same 1 kg mass if it were 6.4 x 10^6 m above Earth's surface.
F = 9.77 N F = 2.44 N
A rocket of mass 50000 kg undergoes an acceleration of 2.6 m/s^2. Find the net force acting on it
Fnet = 1.3 x 10^5 N
A simple rearrangement of Newton's second law gives Fnet = ma. Find a net force that is needed to give a 17-kg package an acceleration of 6 m/s ^2
Fnet = 100 N
Find the impulse on a baseball that is hit with 70 N of force in a time of .50s.
Impulse = 35 N*s
If you remove two protons and two neutrons from a gold atom (Au), what new element is formed (if any)?
Ir
Which of the following statements does not describe a proton?
It orbits around the nucleus of an atom
Which contributes more to an atom's mass: electrons or protons? Which contributes more to an atom's size?
Mass: protons Size: electrons
Which of the following diagrams best represents the size of the atomic nucleus relative to the size of the atom?
The empty circle
Which has more momentum after firing, the cannonball or the recoiling cannon?
They are the same
Does it make sense to say that a textbook is about 99.9 percent empty space?
Yes. A textbook like all material things is made up of atoms, which are considered to be 99.9% empty space.
Use the acceleration formula to find the acceleration of a cart on an inclined plane that gains 5.6 m/s each 1.2 s
a = 4.7 m/s^2
Which statement best describes a compound?
a material that is made up of atoms of different elements bonded together
Which of the following has the largest momentum relative to Earth?
a pickup truck speeding along a highway
When you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing and the average force your body experiences is reduced by
about 10 times
If the mass of an object does not change, a constant net force on the object produces constant
acceleration
Which of the following images could describe an element at the atomic level?
all of the images
If Earth's mass doubled without changing its size, your weight would...
also double
If Earth's mass somehow doubles with no change in its size, and your mass remains the same, your weight
also doubles
When you simultaneously drop a light tennis ball and a heavy bowling ball, they hit the floor
at the same speed
A heavy object and a light object in a vacuum are dropped at the same time from rest. The heavier object reaches the ground
at the same time
A given net force propels an object along a straight-line path. If the mass were doubled, its acceleration would
be half
When driving on the highway, a lovebug spatters onto your windshield. Which experiences the greater force of impact? Which undergoes the greater impulse?
both at the same time, but with different consequences both at the same time
To steadily (constantly) increase the velocity of something requires a
constant net force
When an average force F is exerted over a certain distance on a shopping cart of mass m, its kinetic energy increases by 1/2mv^2 Use the work energy theorem to find the distance over which the force acts If fourfold the force is exerted over fourfold the distance, how does the resulting increase in kinetic energy cause the original increase in kinetic energy?
d = mv^2/2F ΔK2/ΔK1 = 16
Which of the following would be considered applied research?
determining the lightest and strongest metal to be used for an airplane wing
Whereas impulse involves the time that a force acts, work involves the
distance that a force acts
When the speed of an object is doubled, its momentum
doubles
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them doesn't change, then the force between them is
four times as much
Which of the following is an example of a chemical change?
gasoline turning into exhaust
According to Newton, the greater the masses of interacting objects, the
greater the gravitational force between them
If an object's mass is decreasing while a constant force is applied to the object, the acceleration
increases
The massive ram of a pile driver falling from rest strikes a pile with a speed that depends on the
initial height of the ram, initial potential energy of the ram, distance the ram falls --all of the above
If the sun were twice as massive
its pull on Earth would double & Earth's pull on the sun would double
If a charging rhinoceros has momentum, it must also have
kinetic energy
According to Newton, the greater the distance between gravitationally interacting objects, the
less gravitational force between them
An object may have potential energy because of its
location
When you can't escape being hit by a fast-moving object, you'll suffer a smaller force if the collision time is
long
When a cannon fires a cannonball at a given speed, the smaller recoil speed of the cannon is due to different
masses
Chemistry is the study of
matter & transformation of matter
A heavy truck and a small truck roll down a hill. Neglecting friction, at the bottom of the hill, the heavy truck has greater
momentum
A cat and a mouse run along a road with the same kinetic energy. The faster runner is the
mouse
An object that has kinetic energy must be
moving
Consider a space pod somewhere between Earth and the Moon, at just the right distance so that the gravitational attractions to Earth and the Moon are equal. Is this location nearer Earth or the Moon?
nearer the moon
A sample of iron weighs more after it rusts because
of the oxygen it contains
If you push for an hour against a stationary wall, you do no work
on the wall
How many electrons are there in the third shell of sodium, Na (atomic number 11)?
one
Consider a space probe three times as far from Earth's center. Compared at Earth's surface, its gravitational attraction to Earth at this distance is about
one-ninth as much
According to the law of energy conservation, energy can be
only transferred or transformed
Find the momentum for a 3-kg brick parachuting straight downward at a constant speed of 7.6 m/s
p= 23 kg*m/s
As a bowling ball that rolls off the edge of a table falls, its horizontal component of motion
remains constant
A rock is thrown upward at 50° with respect to the horizontal. As it rises, its horizontal component of velocity
remains unchanged
The force that directly propels a motor scooter along a highway is that provided by the
road
If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in
straight line
Newton discovered
that gravity is universal
You're in an airplane that flies horizontally with speed 1200 km/h (330 m/s) when an engine falls off. Ignore air resistance and assume it takes 33 s for the engine to hit the ground. Show that the airplane is 4.5 km high If the airplane somehow continues to fly as if nothing happened, where is the engine relative to the airplane at the moment the engine hits the ground?
y = 5t^2 = 5(33)^2 = 5445m/1200 = 4.53 km high The engine is directly below the airplane
When a rock thrown straight upwards gets to the exact top of its path, its velocity is
zero and its acceleration is 10 m/s^2
If a block is moving to the left at a constant velocity, what can one conclude? A block of a mass of 2 kg is acted upon by two forces: 3 N (directed to the left) and 4 N (directed to the right). What can you say about the blocks motion? A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be Two forces of magnitude 4 N and 10 N, are applied to an object. The relative direction of the forces is unknown. The net force acting upon the object
the net force applied to the block is zero it could be moving to the left, moving to the right, or be instantaneously at rest moving with a constant nonzero acceleration cannot have a magnitude equal to 5
An object at rest cannot remain at rest unless which of the following holds?
the net force being acted on it is zero
If you push an object twice as far while applying the same force, you do
twice as much work
Rating an auto in a service station requires work. Raising it twice as high requires
twice the work
A moving object has
velocity, momentum, energy, speed --all of the above
A "weightless" astronaut in an orbiting space vehicle is
without a support force
