Chapter One
When you push a crate across a level floor at constant speed, friction between the crate and the floor is
the same amount as your pushing force
Compared with a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much
volume, inertia, mass, all of the above
If you toss a ball straight upward at 40 m/s with no air resistance, one second after it reaches the top of its path its speed is
zero
The speed of a vertically-thrown ball at the top of its path is
zero
An object is pulled with two forces, 10 N northward and 15 N southward. The magnitude of the net force is
5 N
One-half second after starting from rest, a freely falling object will have a speed of about
5 m/s
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
50 N to the left
An object in free fall has a speed of 60 m/s. One second later its speed is
70 m/s
You're driving in a car at 50 km/h and bump into a car ahead traveling at 48 km/h in the same direction. The speed of impact is
2 km/h
The average speed of a horse that gallops a distance of 10 km in a time of 30 min is
20 km/h
If a freely falling object were somehow equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s2 , then its speed reading would increase each second by
20 m/s
A man weighing 800 N stands at rest on two bathroom scales so that one scale shows a reading of 500 N. The reading on the other scale is
300 N
If a Jaguar sports car accelerates from zero to 100 km/h in 3.0 s its acceleration is
33.3 km/h/s
The average speed of a deer traveling a distance of 2 km in a time of one-half hour is
4 km/h
Burl and Paul have a total weight of 1300 N. The tensions in the ropes that support the scaffold they stand on add to 1700 N. The weight of the scaffold itself must be
400 N
An object that has twice as much mass as another object also has twice as much
inertia
A glance at your speedometer will tell you your
instantaneous speed
The acceleration of a cart moving down an inclined plane (a ramp)
is constant
When a ball increases in speed by the same amount each second, its acceleration
is constant
Whenever the net force on an object is zero, its acceleration
is zero
Galileo said that if you rolled a ball along a level surface it would
keep rolling without slowing down if no friction acted upon
On the surface of the Moon where acceleration due to gravity is less, a person's hang time would be
longer
A kilogram is a measure of an object's
mass
An object is pulled with three forces: one at 20 N to the right, another at 40 N to the right, and the third at 30 N to the left. The net force is
none of the above
According to Galileo, inertia is a
property of all matter
Your weight is
the gravitational attraction between you and Earth
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by about
10 m/s
The gain in speed each second for a freely falling object is about
10 m/s
When a falling object gains 10 m/s each second, its acceleration is
10 m/s^2
A 50-N object falling in air experiences 50 N of air resistance. The amount of net force on the falling object is
0 N
The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is
10 N
The scientist to first introduce the concept of inertia was
Galileo
You would have the largest mass of gold if it weighed 1 N on the
Moon
When you stand at rest on a pair of bathroom scales, the readings on the scales will always
add to equal your weight
You hang from a pair of gym rings and the upward support forces of the rings will always
add up to equal your weight
You're lying on the sand on a breezy day when a pesky fly wishes to join you. The breeze is blowing at a steady 2 m/s. In order for the fly to land on you it should hover over you while flying
against the breeze at 2 m/s
A motor scooter undergoes acceleration when it
all of the above
An object in mechanical equilibrium is an object
all of the above
The resistive force of friction occurs for
all of the above
While a crate rests on a horizontal floor the friction force acting on the crate is
between zero and the weight of the crate
The equilibrium rule F = 0 applies to
both
Aristotle motion by
classifying it into two classes
When sign painters Burl and Paul stand on opposite ends of a scaffold, the tensions in each of the two supporting ropes
depend on the relative weights of Burl and Paul
The two measurements necessary for calculating average speed are
distance and time
A parachutist falling at constant velocity is in a state of
dynamic equilibrium
In contrast to Aristotle's way of explaining nature, Galileo relied on
experiment