SCI 1600 Exam 2
A bungee jumper attains a speed of 30 m/s just as the bungee cord begins to stretch. If the period of stretch is 2 s, the magnitude of the jumpers average deceleration is about
A: 1.5g
Disregarding air drag, how fast must you toss a ball straight up in order to remain in the air for a total time of 2 s?
A: 10 m/s
A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has
A: 16 times the KE
A 4-kg ball has a momentum of 12-kg m/s. What is the ball's speed?
A: 3 m/s
Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power does the elevator use?
A: 50 W
What is the force of gravity on a 500-N woman standing on the Earth's surface?
A: 500 N
A projectile is launched at ground level an angle of 5 degrees above the horizontal and lands down range. What other projection angle for the same speed would produce the same down-range distance?
A: 75 degrees
A satellite near the Earth makes a full circle in about an hour and a half. How long would a satellite located as far away as the moon take to orbit the Earth?
A: about 28 days
For the astronauts inside an orbiting space vehicle, there is no force of Earth's gravity acting on them. This statement is
A: always false
Inside a freely falling elevator, there would be no
A: apparent weight for you
A cannon recoils from firing a cannonball. The speed of the cannon's recoil is small because the
A: cannon has more mass than the ball
If Earth's mass decreased to one-half its original mass with no change in radius, then your weight would
A: decrease to one-half your original weight
According to Newton, doubling the distance between two interacting objects
A: divides by 4 the gravitational force between them
If the radius of the Earth somehow decreased with no change in mass, your weight would
A: increase
If the mass of the earth somehow increased with no change in radius, your weigh would
A: increase also
Two objects have the same size and shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater
A: momentum
Minimal orbit speed about Earth is about 8 km/s. Minimal orbital speed about Jupiter would be
A: more than 8 km/s
A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it. They stick together and move at a speed of
A: none of these -8 m/s -4 m/s -6 m/s -3 m/s
A rifle recoils from firing a bullet. The speed of the rifle's recoil is small because the
A: rifle has more mass than the bullet
A flower pot of mass m falls from rest to the ground below, a distance h. Which statement is correct?
A: the KE of the pot when it hits the ground is proportional to h
Which is most responsible for the ocean tides?
A: the moon
What is the force of gravity on a 200-N woman standing on the earth's surface?
B: 200 N
Which of the following has the largest momentum relative to the Earth?
B: a pickup truck speeding along a highway
Earth satellites are typically more than 100 km high so as to be above the Earth's
B: atmosphere
A supplier wants to make a profit by buying metal by weight at one altitude and selling it at the same price per pound at another altitude. The supplier should
B: buy at a high altitude and sell at a low altitude
If a satellite's radial velocity is zero at all times, its orbit must be
B: circular
During an eclipse of the sun the high ocean tides on Earth are
B: extra high
A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun
B: if the mass of the bullet equals the mass of the gun
According to Newton, the greater the distance between masses of interacting objects, the
B: less the gravitational force between them
A moving object on which no forces acting will continue to move with constant
B: momentum
The best time for digging clams (when the low tide is extra low) is during the time of the
B: new or full moom
The force of gravity acts on a all apples on an apple tree . Some apples are twice as far from the ground as others. These twice as high apples, for the same mass, have
B: practically the same weight
A projectile is fired vertically from the surface of the Earth at 5 km/s. The projectile will
B: rise and fall back to the Earth's surface
It is correct to say that impulse is equal to
B: the change in momentum
The fastest moving planet in a solar system is
B: the planet nearest the sun
Which pulls on the oceans of the Earth with the greater force?
B: the sun
If you push an object twice as far while applying the same force, you do
B: twice as much work
If an astronaut whose total mass is 100 kg ejects 0.1 kg of has at a speed of 50 m/s from her propulsion pistol, her recoil speed is
C: 0.05 m/s
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest on the frictionless surface. The speed of the putty there after is
C: 1/6 m/s
Consider massive gliders that slide friction-free along a horizontal air track. Glider A has a mass of 1 kg, a speed of 1 m/s, and collides with Glider B that has a mass of 5 kg and is at rest. If they stick upon collision, their speed after collision will be
C: 1/6 m/s
A ball is mocing at 4 m/s and has a momentum of 48 kg\97 m/s. What is the ball's mass?
C: 12 kg
A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is
C: 2000 N
A woman who normally weighs 200 N stands on top of a very tall ladder so she is one Earth-radius above the earth's surface. How much would she weigh there?
C: 50 N
The planet Jupiter is about 300 times as massive as the earth, yet on its surface you would weigh only about 3 times as much. This is because
C: Jupiter's radius is 10 times the earth's radius
The impulse-momentum relationship is a direct result of
C: Newton's second law
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. In this way the average force your body experiences is reduced by
C: about 10 times
It takes 6 s for a stone to fall to the bottom of a mine shaft. How deep is the shaft?
C: about 180 m
Thrown an object upward at a 45 degree angle. With no gravity it will follow a straight line path. But because of gravity, at the end of 1 second, it is
C: about 5 m below the straight line
A feather and a coin dropped in a vacuum fall with equal
C: accelerations
The amount of gravitational force acts on the space shuttle while in orbit is
C: almost as much as the shuttle's weight on the earth's surface
No force due to Earth's gravity is acting on the astronauts inside the orbiting space shuttle. This statement is
C: always false
Inside a freely-falling runaway elevator, your
C: apparent weight is zero
Earth's gravitational field extends
C: both inside and outside the earth and throughout the entire universe
You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum?
C: both the same
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity
C: decreases
A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is
C: doubled
The force that accelerates a rocket in outer space is exerted on the rocket by
C: exhaust gases
An Earth satellite is simply a projectile
C: freely falling around the Earth
Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each
C: increases
When the distance between two stars decreases by half, the force between them
C: increases to four times as much
A "weightless" astronaut in an orbiting shuttle is
C: like the shuttle, pulled by Earth's gravitation
An object that has kinetic energy must be
C: moving
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity
C: remains unchanged
A black hole is
C: simply the remains of a giant star that has undergone gravitational collapse
Compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because the
C: stopping time is longer on the carpet
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is
C: the same
If an object is raised twice as high, its potential energy will be
C: twice as much
Tidal forces in general are the result of
C: unequal forces acting on different parts of a body
An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a ground speed of
D: 141 km/h
A 2-kg mass has 40 J of potential energy with respect to the ground. Approximately how far is it located above the ground
D: 2 m
A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?
D: 40 J
A 5-kg fish swimming at a speed of 1 m/s swallows an absent minded 1-kg fish at rest. The speed of the larger fish after lunch is
D: 5/6 m/s
A car's engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of gasoline is 40 megajoules per liter, how many kilometers per liter does the car get?
D: 8
The force on an apple hitting the ground depends on
D: all of these - whether or not the apple bounces -the time of impact with the ground -the speed of the apple just before it hits
A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has
D: all of these -more momentum -more mass -less stopping distance
There are no tides to be seen in the community swimming pool because
D: all parts of it are practically the same distance form the Moon
How far must one travel to get away from the Earth's gravitational field?
D: forget it, you can't travel far enough
Compared to the force that brings a small car to a stop, the force required to bring a heavy truck to a stop
D: impossible to determine without additional information
An object that has potential energy may have this energy because of its
D: location
Half-way to the center of a planet of uniform density, your weight compared to that at the surface would be
D: one-half
In order 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 upon impact. Doing this reduces the force of impact on the player's hand principally because the
D: time of impact is increased
A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of
E: 1 kg m/s
Padded dashboards in cars are safer in an accident than non-padded ones because an occupant hitting the dash has
E: A and C above -decreased impact force -increased time of impact
What prevents satellites such as the space shuttle from falling?
E: Nothing, they are continually falling as they orbit the Earth
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
E: increases
A woman who normally weighs 400 N stands on top of a very tall ladder sos he is one Earth radius above the Earth's surface. How much would she weigh there?
E: none of these -400 N -100 N -zero -200 N
Consider two planets in space that gravitationally attract each other. If the masses of both planets are doubled, and the distance between them is also doubled, then the force between them is
E: none of these -four times as much -twice as much -half as much -one quarter
A 1- N apple falls to the ground. The apple hits the ground with an impact force of about
E: not enough information give to say
No work is done by gravity on a bowling ball that rolls along a bowling alley because
E: the force on the ball is at right angles to the ball's motion