Final Exam. Flashcards
A scientific hypothesis may turn out to be right or it may turn out to be wrong. If it is a valid hypothesis, there must be a test for proving it…
wrong.
Which one of the following is a scientific statement?
A. There are things we will never know about.
B. The moon is made of green cheese.
C. Matter is filed with undetectable particles
D. There are parts of the universe that will never be found by man.
B. The moon is made of green cheese.
When a rocket ship accelerating in outer space runs out of fuel it..
accelerates for a short time, and then slows down to a constant velocity.
Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to..
follow a straight line path.
An object in mechanical equilibrium can be an object... A. at rest B. having no acceleration C. moving with constant veocity D. all of these.
D. all of these
What is the weight of a 200-kg bear?
2000 N
A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor…
exactly below the midpoint of the ceiling.
Which one of the following descriptions violates Newton’s first law of motion?
A. a glass of water is sitting on a table in the dining car of a train. The train brakes as it nears the station, and the glass slides forward.
B. A child is sitting in the back seat of a car and is not wearing a seat belt. The car is traveling forward and the driver suddenly applies the brakes. The child flies forward against the rear side of the front seat.
C. A small suitcase is at the front of the overhead luggage compartment on an airplane. When the airplane begins its takeoff, the suitcase slides to the rear of the compartment.
D. A rabbit’s foot is hanging on a chain from the rearview mirror of a car. As the car accelerates forward, the rabbits foot swings toward the windshield.
D. A rabbit’s foot is hanging on a chain from the rearview mirror of a car. As the car accelerates forward, the rabbits foot swings toward the windshield.
A horse gallops a distance of 20 kilometers in a time of 30 minutes. It’s average speed is…
40 km/h
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 a constant velocity is…
zero.
Twelve seconds after starting from rest, an object falling freely on Earth will have a speed of…
more than 100 m/s
A bal is thrown upwards and returns to the same position. Compared with it’s original speed after release, its speed when it returns is about…
twice as much.
Someone standing at the edge of a cliff throws one ball straight up and another ball straight down at the sam initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed will be…
A. the one thrown upwards
B. the one thrown downwards.
C. neither, they will both hit with the same speed.
C. neither, they will both hit with the same speed.
Your weight is..
the gravitational attraction force between you and the Earth.
If one object has twice the mass of another object, it also has twice as much..
inertia.
Strange as it may seem, it is just as hard to accelerate a car on a level surface on the moon as it is here on Earth. This is because…
The mass of the car is independent of gravity.
When a falling object has reached it’s terminal velocity, it’s acceleration is…
zero.
An object is propelled along a straight-line path in space by force. If the mass of the object somehow becomes twice as much with force remain unchanged, its acceleration…
halves.
Which has zero acceleration? An object... A. at rest B. In mechanical equilibrium. C. Moving at constant velocity D. all of these
D. all of these.
An object is pulled northward by a force of 15 N and at the same time another force of 25 N pulls it southward. The magnitude of the resultant force on the object is..
10 N
For an action force, there must be a reaction force that…
is exactly equal in magnitude.
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…
Force the glove exerts on the ball.
A Mack truc and a volkswagon traveling at the same speed have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the…
volkswagon.
The attraction of a person’s body toward Earth is called weight. The reaction to this force is…
the person’s body pulling the Earth.
Which one of the following is true, according to Newton’s laws of motion (remember all three laws)? Ignore friction.
A. A semitrailer truck crashes all the way through a wall. Since the wall collapses, the wall sustains a greater force than the truck does.
B. Two astronauts on a space walk are throwing a ball back and forth between each other. In this game of catch the distance between them remains constant.
C. Sam (18 years old and larger) and his sister (9 years old) go ice skating. The push off against each other and fly apart. Sam flies off with the greater acceleration.
D. A sports utility vehicle (SUV) hits a stationary motorcycle. Since it is stationary, the motorcycle sustains a greater force than the SUV does.
E. None of these are true, according to the third law.
E. None of these are true, according to the third law.
It is correct to say that impulse is equal to…
the change in momentum it produces.
Suppose that a tiny gun made of strong but very light material fires a bullet that is more massive than the gun itself. For such a weapon…
the target would be safer than the shooter because the weapon’s recoil would be dangerous.
To catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball’s motion. Doing this reduces the force of impact on the player’s hand principally because the…
Time of impact is increased.
A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. More stopping force is required when the car has... A. more mass B. more momentum C. less stopping distance. D. all of these
D. all of these
Two billiard balls having the same mass and speed roll towards each other. What is their combined momentum after they meet?
zero
Two train cars both with a mass of 1000 kg are on a track. The one train car is at rest while the other is moving towards it at 6 m/s. The two cars collide and couple together. What is the final speed of the coupled train cars after the collision?
3 m/s
If you push an object twice as far while applying the same force, you do
twice as much work.
If you do work on an object in one-thirde the usual time, your power output is…
three times the usual power output.
Say that an object is lifted 5 meters gains 400 J of potential energy. If the same object is lifted 10 meters, its potential gain is..
twice as much.
An object that has kinetic energy must be…
moving
When an automobile is braked to a stop, its kinetic energy is transformed to…
heat
Compared to the recoiling rifle, the bullet fired has…
a greater kinetic energy.
Which moves faster in m/s on a merry-go-round: a horse on the inside or a horse on the outside near the outer rail?
outside horse.
A broom is easier to balance on it’s end when the heavier end (the brush end) is…
highest, farthest from your hand.
Torque acting on an object tends to produce…
rotation.
The chef at the infamous fattening tower of pizza tosses a spinning disk of uncooked pizza dough into the air. The disk’s diameter increases during the flight, while its rotational speed…
decreases.
according to newton, doubling the distance between two interacting objects…
divides by 4 the gravitational force between them.
An asteroid exerts a 360 N gravitational force on a nearby spacecraft. This force is directed…
towards the asteroid.
If the radius of the Earth somehow decreased with no change in mass, your weight would (hint: think how the earth’s gravity would change with a shorter separation distance)
increase.
When the distance between two stars decreases by half, the force between them…
increases to four times as much.
Roll a bowling ball off the edge of the table. As it falls, its horizontal component of velocity…
remains constant.
A projectile is launched vertically upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is…
50 m/s.
A projectile is fired horizonally in a region of no air resistance. The projectile maintains its horizontal component of velocity because..
it is not acted on by any horizontal forces.
A bullet fired horizontally over level ground hits the ground in 0.5 seconds. If it had been fired with twice the speed in the same direction, it would have hit the ground in…
Exactly 0.5s.
Which of the following are electrically neutral? A. proton B. electron C. ion D. neutron
D. neutron
Which of these atoms has the most mass? A. Uranium B. Lead C. Iron D. Hyrdrogen
A. Uranium
In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of…
orbital electrons.
The chemical properties of matter come mostly from its…
electrons.
If one neutron is added to a helium nucleus, the result is an isotope of…
helium.
When a chocolate bar is cute in half, its density is…
unchanged.
if a loaf of bread is compressed, its…
density increases.
If the mass of an object were to double while its volume remains the same, its density would…
double.
A wooden block has a mass of 1000 kg and a volume of 2 cubic meters. What is the block’s density?
500 kg per cubic meter.
A strong spring is stretched 10 cm by a suspended weight. If the weight is doubled, the spring will stretch…
another 10cm, making the total stretch 20 cm.