Scen 101 - Exam 1 Questions
A machine puts out 100 W of power for every 1000 W put in. The efficiency is
10%
What is the weight of the water displaced by a 100 ton floating ship?
100 tons
Escape speed from Earth is
11.2 km/s
A tow truck exerts a force of 3000 N on a car that accelerates 2 m/s^2. The mass of the car must be
1500kg
A shopping cart moves with a KE of 40 J. If it moves twice its speed, KE is
160J
Fido weighs 120 N and carries Trixie who weighs 40 N on his back. The support force Fido feels is
160N
A girl pushes a cart to the left with a 100 N force A boy pushes it to the right with a 50 N force. The net force exerted on the cart is
50N to the left
Which of the following has the greatest momentum relative to Earth?
a pickup truck speeding along a highway
An umbrella tends to jerk upwards on a windy day principally because
air pressure is reduced over the curved top surface
Which of these is a scientific hypothesis?
an atom is the smallest bit of matter in a material
As water in a confined pipe speeds up, the pressure it exerts against the inner walls of the pipe
decreases
If a loaf of bread is compressed
density increases
A given net force propels an object along a straight line path. If net force doubles, its acceleration would
double
A parachutist falling at constant velocity is in
dynamic equilibrium
Successes in science is mainly linked to emphasis on
experiments
According to Newton, greater masses of interacting objects,
greater gravitational force
Scientific equations in a conceptual course are mainly
guides to thinking about the relationship between concepts
Lifting 100 N load with 50 N force lifts it
half as high
A ball rests in the middle of a cart. When you quickly jerk the cart forward, the ball
hits the back of the cart
In science, an educated guess is a
hypothesis
In a vacuum, a marshmallow becomes
larger
The lunar month is 28 days. If the moon were closer to Earth than it is now, the lunar month would be
less than 28 days
The force exerted on the tires of a car to directly accelerate it along a road is exerted by the
road
A mack truck and a mini cooper travelling at the same speed collide head on. The collision force is greater on the
same
Which requires more work on car brakes?
slowing down from 100 km/h to 70 km/h
The statement "there are regions of earth's crust beyond investigation" is
speculation
A moving object has
speed, momentum, velocity, energy
Whirl a rock at the end of a string and it will follow a circular path. If the string breaks, it will continue in a
straight line path
The ultimate source of energy from fossil fuels is from the
sun
In science, a theory is a
synthesis of a large body of well tested knowledge
A truly educated person is knowledgeable about
the arts, science, religion (all of the above)
Exert 100 J in 50 s and your power output is
2 W
A car has a mass of 1000 kg and accelerates at 2 m/s^2. What is the force?
2000N
If a projectile is fired straight up at a speed of 10 m/s, neglecting air resistance, the total time to return to its starting position is
2s
A girl pulls on a 10 kg wagon with a constant force of 30 N. What's the wagon's acceleration?
3 m/s^2
A 3000 N bear grasping a vertical tree slides down at constant velocity. The friction force between the tree and the bear is
3000N
A karate chop breaks a board with a force of 3000 N. The force acting on the hand is
3000N
If a ball rolls down an inclined plane and picks up 4 m/s each second it rolls, acceleration is
4 m/s^2
A projectile is thrown into the air at an angle of 50 degrees and lands on a target that is at the same level the projectile started. With no air resistance it will also land on the target if it is thrown at an angle of
40 degrees
Aristotle believed natural laws are understood by
logic
In contrast to Aristotle's way of explaining nature, Galileo relied on
logic
A kilogram measures
mass
The language of science is
mathematics
If the masses of two planets double and the distance between them reduces by half, the force between them would be
none of the above - answer on exam 16 times greater - numerical answer
A scientific hypothesis can be disproved with
one reproducible experiment
When you stand on a scale on your tiptoes, there's an increase in
pressure on the scale, not registered as weight
Compared to a bar of pure gold, density of a gold ring is
the same
Compared to the buoyant force of the atmosphere on a 1-L helium balloon the buoyant force on a 1-L solid iron block is
the same
A car travelling at 100 km/h strikes an unfortunate bug that splatters on a windshield. The force of impact is greater on
the same for both
Atmospheric pressure is caused by
the weight of the atmosphere
In order to catch a softball w your bare hand, extend hand forward and ride back w ball. Doing this reduces catching force because
time of catch is increased
When you push your desk to the right, friction is acting
to the left
Suspend a pair of ping pong balls from two strings so there is a small space between them. If you blow air between them, they will swing
towards each other
If you push an object twice as far while applying same force, you do
twice the work
A change in pressure at any point in a confined fluid at rest is transmitted
undiminished to all points in the fluid
Passengers in a high flying jumbo jet feel their normal weight in flight. Passengers in an orbiting space vehicle do not because passengers are
without support forces
An object in motion stays in motion
without the need of a force
A mack truck and a mini cooper travelling at the same speed collide head on. The collision force is greater on the
wood
A hypothesis that is scientific must have a test proving it
wrong
Whenever net force is zero, acceleration is
zero