Physics Chapter 4

25 July 2022
4.7 (114 reviews)
43 test answers

Unlock all answers in this set

Unlock answers (39)
question
The direction of the force of friction on a sliding crate is _______.
answer
opposite to the direction of sliding
question
A crate sits at rest on a factory floor. Friction between the crate and floor occurs _______.
answer
when the crate is pushed horizontally, whether it slides or no
question
The unit of mass is the kilogram, and the unit of weight is _______.
answer
the newton
question
Which of the following depends on gravity?
answer
Weight
question
In considering proportions, acceleration is _______.
answer
inversely proportional to mass
question
When does the proportion form of Newton's second law take the form of an equation?
answer
When units of newtons and kilograms are used for force and mass
question
A 1-kg stone and a 10-kg stone have the same acceleration in free fall because _______.
answer
the ratio of weight to mass is the same for each
question
As a skydiver gains speed in falling through the air, air resistance _______.
answer
increases
question
Air resistance on a parachutist at terminal speed _______.
answer
is greater for a heavier person
question
Since an object weighs less on the surface of the Moon than on Earth's surface, does it have less inertia on the Moon's surface?
answer
No
question
A 400 kg bear grasping a vertical tree slides down at constant velocity. What is the friction force that acts on the bear?
answer
4000 N
question
What weight change occurs when your mass increases by 2 kg?
answer
20.0 N
question
A grocery bag can withstand 300 N of force before it rips apart. How many kilograms of apples can it safely hold?
answer
30.0 kg
question
Free fall is motion in which gravity is the only force acting. Is a skydiver who has reached terminal speed in free fall?
answer
No
question
Is a satellite above the atmosphere that circles Earth in free fall?
answer
Yes
question
Does a falling object increase in speed if its acceleration of fall decreases?
answer
Yes.
question
What is the magnitude of the net force acting on a 1-kg ball in free fall?
answer
10.0 N
question
What is the net force acting on a falling 1-kg ball if it encounters 2 N of air resistance?
answer
8.00 N
question
When a parachutist opens her parachute after reaching terminal speed, in what direction does she accelerate?
answer
up
question
Which has the greater mass? an automobile battery a king-size pillow neither - both have the same
answer
an automobile battery
question
Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same... weight. mass. volume. all of these none of these
answer
none of these
question
Compared to the mass of a certain object on Earth, the mass of the same object on the moon is...
answer
the same.
question
The newton is a unit of
answer
force
question
An object's weight may properly be expressed in units of
answer
newtons.
question
Calculate the weight in newtons of a 2.9-kg melon. Weight = mg
answer
W = 29 N
question
Calculate the acceleration of a 2000-kg, single-engine airplane just before takeoff when the thrust of its engine is 400 N . Acceleration: a=Fnet/m
answer
a = 0.20 ms^2
question
Calculate the horizontal force that must be applied to a 1.2-kg puck to make it accelerate on a horizontal friction-free air table with the same acceleration it would have if it were dropped and fell freely. Force = ma
answer
F = 12 N
question
If your friend Katelyn weighs 460 N , what is her weight in pounds?
answer
W = 104 lb
question
Consider a business jet of mass 32000 kg in takeoff when the thrust for each of two engines is 24000 N . Find its acceleration.
answer
a = 1.5 m/s^2
question
A skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on the diver is then
answer
500 N.
question
A heavy rock and a light rock of the same size are falling through the air from a tall building. The one that encounters the greatest air resistance is the
answer
heavy rock
question
A falling skydiver of mass 100 kg experiences 500 N of air resistance. The acceleration of the skydiver is
answer
0.5 g.
question
The human body can, under certain conditions, withstand an acceleration of 10 g. What net force would produce this acceleration of a 50-kg person?
answer
about 5000 N
question
A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was
answer
30 m/s.
question
A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about
answer
10 N
question
A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface?
answer
6 N
question
A push on a 1-kg brick accelerates it. Neglecting friction, to equally accelerate a 10-kg brick, one would have to push with
answer
10 times as much force.
question
An object following a straight-line path at constant speed
answer
has zero acceleration.
question
A force of 1 N accelerates a mass of 1 kg at the rate of 1 m/s2. The acceleration of a mass of 2 kg acted upon by a net force of 2 N is
answer
the same.
question
A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car?
answer
2000 N
question
The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is
answer
10 N.
question
An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be
answer
twice as much.
question
A skydiver's terminal velocity will be greatest if she falls
answer
head first.