Physics Exam 2
A projectile is launched at ground level an angle of 15 degrees above the horizontal and lands down range. What other projection angle for the same speed would produce the same down-range distance?
75 degrees
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?
8
The best time for digging clams (when the low tide is extra low) is during the time of the
new or full moon
Two objects move toward each other because of gravity. As the objects get closer and closer, the acceleration of each
increases
Two objects move toward each other because of gravity. As the objects get closer and closer, the force between them
increases
Minimal orbital speed about the Earth is about 8 km/s. Minimal orbit speed about the moon would be
less than 8 km/s
A "weightless" astronaut in an orbiting shuttle is
like the shuttle, pulled by Earth's gravitation
Which is most responsible for the ocean tides?
the moon
The fastest moving planet in a solar system is
the planet nearest the sun
The force on an apple hitting the ground depends upon
the speed of the apple just before it hits the time of impact with the ground whether or not the apple bounces
Which pulls on the oceans of the Earth with the greater force?
the sun
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
Consider a hydraulic press. When the input is depressed 20 cm, the output piston is raised 1 cm. On the same press, an input force of 1 N can lift a load of
1 N 10 N 15 N 20 N All of the above are correct
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
1 kg m/s
A 1 kg chunk of putty moving at 1 m/s collides with and sticks to a 5 kg bowling ball that is initially at rest on a frictionless surface. The speed of the putty thereafter is
1/6 m/s
An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a ground speed of
141 km/h
A car moves 4 times as fast as another identical car. Compared to the slower car, the faster cas has
16 times the KE
Do 100 J of work in 50 s and your power output is
2 W
A 1000 kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is
2000 N
A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?
3 m/s
A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?
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 this lunch is
5/6 m/s
Using 100 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was
50 W
What is the force of gravity on a 500-newton woman standing on the Earth's surface?
500 N
An object is placed exactly halfway between the Earth and moon. The object will fall toward the
Earth
The planet Jupiter is about 300 times as massive as Earth, yet on its surface you would weigh only about 3 times as much . This is because
Jupiter's radius is 10 times the Earth's radius
The impulse-momentum relationship is a direct result of
Newton's 2nd Law
What prevents satellites such as the space shuttle from falling?
Nothing, they are continually falling as they orbit the Earth
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?
about 28 days
Throw 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
about 5 m below the straight line
A feather and coin dropped in a vacuum fall with equal
accelerations
No force due to Earth's gravity is acting on the astronauts inside the orbiting space shuttle. This statement is
always false
Inside a freely falling elevator, there would be no
apparent weight for you
Inside a freely falling runaway elevator, your
apparent weight is zero
Earth satellites are typically more than 100 km high so as to be above the Earth's
atmosphere
If a satellite's radial velocity is zero at all times, its orbit must be
circular
According to Newton, doubling the distance between two interacting objects
divides by 4 the gravitational force between them
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
doubled
During an eclipse of the sun the high ocean tides on Earth are
extra high
An Earth satellite is simply a projectile
freely falling around the Earth
If the radius of the Earth somehow decreased with no change in mass, your weight would
increase
When an automobile is braked to a stop, its kinetic energy is transformed to
heat
A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun
if the mass of the bullet equals the mass of the gun
Compared to the force that brings a small car to a stop, the force required to bring a heavy truck to a stop
impossible to determine without additional information
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
momentum
An object that has kinetic energy must be
moving
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
none of these
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
none of these
Half way to the center of a planet of uniform density, your weight compared to that at the surface would be
one-half
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its horizontal component of velocity
remains unchanged
A rock is thrown upward at 50 degrees with respect to the horizontal. As it rises, neglecting air drag, its vertical component of velocity
remains unchanged
A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because
rifle has much more mass than the bullet
A projectile is fired vertically from the surface of the Earth at 5 km/s. The projectile will
rise and fall back to the Earth's surface
Which of the following is not a vector quantity?
speed
It is correct to say that impulse is equal to
the change in momentum it produces
No work is done by gravity on a bowling ball that rolls along a bowling alley because
the force on the ball is at the right angles to the ball's motion
If an object is raised twice as high, its potential energy will be
twice as much
If you push an object twice as far while applying the same force, you do
twice as much work
Tidal forces in general are the result of
unequal forces acting on different parts of a body