Physics Lesson 1
The net force on a 1 N apple held over your head is
0 N
An object travels 80 meters in one minute, another 80 m in the next one minute, and another 80 m in the next one minute. It's acceleration is about
0 m/s per minute - doesn't change
Galloping 10 kilometers in 30 minutes, the average speed of a horse is
0.5 mph = 20 km/h
Assuming no friction, 1 kg block accelerates after being pushed. To get the same acceleration, a 10 kg block would have to be pushed with
10 times as much force
on a horizontal table with no friction are rested two blocks of weights 1 n and 10 n. for equal acceleration, we would need to push with
10 times as much force on the heavier block
Starting from rest, a car accelerates 2 m/s per second. In 10 seconds it will travel
100 m
A bat hits a baseball with a force of 1000 N. The force the ball exerts on the bat is
1000 N
Starting from rest and accelerating at 2 m/s per second, how long does it take a car to get to a speed of 30 m/s?
15 seconds
A tow line pulls a car with 3000 N causing an acceleration of 2 m/s per second. The mass of the car must be about
1500 kg
While taking off, each of the four engines of a jumbo jet exerts a thrust of 50,000 N. At 100,000 kg, the acceleration of the jet is about
2 m/s per second
An object is dropped on a planet where the acceleration due to gravity is twice that of Earth. After free-falling for one second, its speed is
20 m/s
With a mass of 1000 kg, a car accelerates at 2 m/s per second. The new force on the car must be about
2000 N
a drone flying at 22 m/s comes to a quick stop in 0.1 second upon hitting a tree. its deceleration is
220 m/s per second
When a 10 kg wagon is pulled upon with a steady horizontal net force of 30 N, then the wagon's acceleration is
3 m/s per second
With 10,000 N of braking, a 2000 kg truck stops in 6 seconds. The truck's speed before braking was
30 m/s
A 600 N man has his weight evenly distributed across two scales. On each scale the reading is..
300 N
a 1000 kg car takes 10 seconds to accelerate uniformly from 10 m/s to 40 m/s. the distance traveled in that time period is
300 m
A rocket starting from rest and accelerating at 50 m/s per second for one minute will have a speed of
3000 m/s (50x60)
a 3000 n karate chop breaks a board. the reaction force on the hand is
3000 n
Accelerating from rest, a car takes 5 seconds to reach 20 m/s. Its rate of acceleration is
4 m/s per second
From standing still, a car gets to 40 m/s in 10 seconds, which gives it an acceleration of
4 m/s/s
An 800 N man stands evenly on two scales. The reading on each scale is
400 N
two people are playing tug-of-war holding their ground but each tugging with a force of 400 n at the ends of the rope. the tension within the rope is
400 n
The resultant force acting on an object being pushed westward at 10 n while also eastward 15 n has a magnitude of
5 n
While you're pulled down to earth by a force of 500 n, the earth is pulled up by a force of
500 n
How many milliliters of air are there in a hole measuring 5 L?
5000 mL
The acceleration of a car going from a velocity of zero to 60 km/h in 10 seconds is
6 km/h/s
Accelerating from rest at 2 m/s per second, a car in 2 seconds will be moving at about
6 m/s
An object falls freely at 50 m/s. One second later its speed should be about
60 m/s
The gravity of the moon is 1/6 that of Earth's. If your mass is 65 kilograms on earth, what is your mass on the moon?
65 kg
On the surface of Earth, a mass of 1 kilogram weighs..
9.8 Newtons
Which of the following is the largest quantity of mass? 100,000,000 mg 100 kg 100,000
All of the masses are the same
What is the nature of science? Science describes order in nature. Science is an ongoing activity of humans. Science condenses knowledge into testable laws.
All of these
Anything in mechanical equilibrium is
At rest, moving with constant velocity, not accelerating: no change
The scientist who is credited for being the first to introduce the idea of inertia was
Galileo
If an item has two times the mass of another item, then it also has two times the
Inertia
A 4 kg chunk of pure lead, compared to a 2 kg chunk, has two times as much
Inertia, mass, volume
What is a liter? Then, which of the follow is not a measurement of volume?
Measurement of liquid volume ; milligrams
Does a 2 kg solid iron brick have twice as much mass as a 1 kg solid block of wood? Twice as much volume?
The iron brick has twice the mass, but its volume compared to the block of wood depends on the weight of the wood
What physical quantities discussed in this chapter change most when a junked car is neatly crushed into a compact cube?
The volume of the car changes as well as its average density
Should the atmospheric ratio of nitrogen molecules to oxygen molecules increase or decrease with increasing altitude?
There should be more nitrogen than oxygen at higher altitudes because nitrogen is less massive
Why do we use different units for mass and weight?
They are two different quantities
How does your weight compare to your mass?
Weight is not the same thing as your mass.
Which would you rather have: a decigram or a kilogram of gold?
a kilogram because it is 10,000 times bigger than a decigram
A 10 N pet frog has a mass of
about 1 kg
A volleyball player who remains airborne for a full 1 second must have jumped
about 1.2 m - 1 second - 12 meters
a 10 kg sack of potatoes has a weight of
about 100 n
a massive package falls from a truck moving 20 m/s. just before hitting the ground its horizontal speed is
about 20 m/s
What is the mass in kilograms of a 130 pound human standing on the moon?
about 350
While driving at 25 m/s you hit the brakes to decelerate at 0.5 g to a full stop. The time it took to stop was
about 5 seconds
to accelerate a 50 kg human to 10 g requires a net force of about
about 5000 N
What is the mass in kilograms of a 130 pound human standing on the Earth?
about 59 kg
Not touching the ground, you sit still on a swing. The upward force on the two ropes of the swing will always..
add up to equal your weight
your buddy says the worlds strongest boxing champion can't punch a hanging sheet of tissue paper with a force of 100 n. knowing physics, you
agree that it can't be done
Without a special filter, the Sun can be safely viewed by looking
at pinhole images
two ice blocks, one large and one small, start to slide down an inclined plane at the same time. assuming no friction, the large block reaches the bottom
at the same time as the small block
At steady acceleration, an object's velocity must
change by the same amount each second
Eratosthenes found the Sun's position on June 22 by
consulting library information
On level ground you apply breaks to slow your car from 60 km/h to 40 km/h. Upon quickly releasing the breaks your car tends to
continue moving at 40 km/h
To calculate average speed you need to measure
distance and time
According to Newton, a moving train should roll forever even with the engine off. But this doesn't happen because the train
encounters friction
You stand with one foot on a bathroom scale and the other foot on an identical scale. Each scale then indicates
exactly half your weight; part of your total weight but not necessarily half of it; different values that will equal your weight when added together
a tree moves at 30 km/s relative to the sun. a squirrel jumps from a branch on this tree to an acorn on the ground. but taking on second to drop, the acorn should then be 30 kilometers away. we can understand why this reasons is wrong by looking to newtons
first law
a bat hits a baseball. the reaction force is
force that the ball exerts on the bat
a baseball hits a players glove. the reaction force is the
force the glove exerts on the ball
a constant force is applied to an object whose mass doubles the acceleration thus
halves
To measure how far between the Moon and Earth you can
hold up a coin
Describe mass. Then, which of the following does not describe mass?
how much space an object occupies (volume)
An object not rotating and with no acceleration is
in mechanical equilibrium
Suspended by a rope a heavy block hangs still. As the block is then pulled upward, the tension in the rope
increases
you run out of gas while driving, but the car doesn't come to an instant stop because of
inertia
for a force that is action, there will be a force that is reaction and
is exactly equal in magnitude
An objects measurement in kilograms is a measurement of its..
mass
What is the difference between mass and weight?
mass is the amount of matter in an object, weight is the measure of the pull of gravity on an object/mass
Which of the following is not a volume measurement?
milligrams
A piece of gold would give you the largest mass if it weighed 1 N on the
moon
The weight of an object is given in units of
newtons
A 4 kg chunk of pure lead, compared to a 2 kg chunk, has the identical...
none of these
As a car goes around a circular track with constant speed its
none of these
compared to when not towing, car towing a trailer twice its mass will have an acceleration that is
one third as much
Earth pulls on a falling ball. The reaction force is
pull of the ball's mass on the earth
a 500 N woman standing on a bathroom scale gently lifts on foot. The reading on the scale
remains 500 N
A car is accelerated down the road by a force exerted by the
road
With inclined planes, Galileo was effectively able to...
slow down the acceleration of free fall
A rock is dropped from the ceiling of a truck's cargo bay. With the truck moving at constant velocity, the rock strikes the floor
straight below
A falling skydiver is pulled down by earth's gravity. the reaction force is
the diver pulling the earth upward
your weight is
the gravitational attraction between you and the earth
Gravity on the moon is only 1/6 as strong as gravity on the earth. What is the mass of a 10 kg object on the moon and on the earth?
the mass of a 10 kg object anywhere is 10 kg
Accelerating a car on a level surface of the moon is just as difficult as on Earth because
the mass of the car is independent of gravity
as a rocket takes off toward outer space it gains in acceleration primarily because
the mass of the rocket decreases as fuel is burned
A car and a mosquito moving with the same speed collide head-on. Which undergoes the greatest deceleration?
the mosquito
A rock on Earth and a rock on the moon each weight 30 N. The one with a greater mass is
the one on the moon
a 1 kg mass is pulled with a net force of 1 n. relative to a 2 kg mass pulled with a net force of 2 n, its acceleration is
the same
the mass of an item on earth compared to its mass on the moon is..
the same
A car and a mosquito moving with the same speed collide head-on. the force of impact is
the same for both
Two county fair bumper cars collide and bounce off each other. One car is 2 times as massive. The force of impact was
the same for both
Describe volume. Then, which of the following does not describe volume?
the weight of a given object
Earth pulls on the moon. Similarly the moon pulls on that, evidence that earths gravity tugs on the moon. Like, the moon's gravity tugs on earth. this is evidence that
these two tugs comprise an action-reaction pair
What is a gram? Then, which of the following represents the largest quantity of mass?
unit of mass ; 24 kilograms
Can an object have mass without having weight? Can it have weight without having mass?
yes and no
