-
SAT
试题
object
that
’
s
moving
with
constant
speed
travels
once
around
a
circular
statements about this
motion include which of the following?
displacement is zero
B. The average
speed is zero
C. The acceleration is
zero
D. None of the above
A
of the following must
always be true?
an
object
’
s acceleration is
constant,then it must move in a straight line
an object
’
s
acceleration is zero,then its speed must remain
constant
an
object
’
s speed remains
constant,then its acceleration must be zero.
A.1 and 2 only
B.1 and 3 only
C.2 only
D.3 only
E.2 and 3 only
C
4.A frictionless inclined
plane of length 20m has a maximum vertical height
of 5m. If an
object of mass 2 kg is
planced on the plame . Which of the following best
approximates the
net force it feels?
A.5N
B.10N
C.15N
D.20N
E.30N
A
5.A person who weighs 800N
steps onto a scale that is on the floor of an
elevator car. If the
elevator
accelerates upward at a rate of 5 m/s
,
what will the scale read?
A.400N
B.800N
C.1000N
D.1200N
E.1600N
D
6.A person standing on a horizontal
floor feels two forces: the downward pull of
gravity
and the upward supporting force
from the floor. There two forces
A.
have equal magnitudes and from an action /reaction
pair
B. have equal magnitudes but do
not from an action /reaction pair
C.
have unequal magnitudes and from an action
/reaction pair
D. have unequal
magnitudes and do not from an action /reaction
pair
of the above
B
long would it take a car,starting from
rest and accelerating uniformly in a straight
line at 5m/s
,to cover a
distance of 200m?
A.9s
B 10.5s
C.12.0s
D.15.5s
E.20.0s
A
8.A rock is dropped off a cliff and
strikes the ground with an impact velocity of 30m/
high was the cliff?
A.15m
B.20m
C.30m
D.45m
E.60m
D
9.A soccer ball at rest on
the ground,is kicked with an initial velocity of
10m/s at a launch
2
2
angle of 30
.Calculate its
total flight time , assuming that air resistance
is negligible.
A.0.5s
B.1s
C.1.7s
D.2s
E.4s
B
all of
the forces acting on an object balance so that the
net force is zero , then
object must
be at rest
B. the
object
’
s speed will decrease
C. the object will follow a parbolic
trajectory
D. the
object
’
s direction of motion
can change,but its speed cannot
of the
above
E
coefficient of
static friction between a box and a ramp is 0.5.
The ramp
’
s incline
angle is 30
.If the box is
placed at rest on the ramp, box will
A.
accelerate down the ramp
B. accelerate
briefly down the ramp but then slow down and stop
with constant velocity down the ramp
move
be determined from
the information given
A
12.A
20N
block
is
being
pushed
across
a
horizontal
table
by
an
18N
force .
If
the
coefficient of kinetic
friction between the block and the table is 0.4.
find he acceleration of
the block
A.0.5 m/s
B.1 m/s
C.5 m/s
D.7.5 m/s
E.9m/s
C
13.A
stone
is
thrown
horizontally
with
an
initial
speed
of
30m/s
from
a
the
stone
’
s total
speed when it enters the water 4 seconds
later(Ignore air resistance.)
A.30m/s
B.40m/s
C.50m/s
D.60m/s
E.70m/s
C
one
of
the
following
statements
is
true
concerning
the
motion
of
an
ideal
projectile launched at an angle of
45
to the borizontal?
acceleration vector points opposite to
the velocity vector on the way up and in the
same direction as the velocity vector
on the way down
speed at the top of
the trajectory is zero.
object
’
s total speed remains
constant during the entire flight
horizontal speed decreases on the way up and
increases on the way down
vertical
speed decreases on the way up and increases on the
way down
E
pair of forces
can produce a resultant of 15 newtons?
A.20N,20N
B.25N,5N
C.5N,5N
D.7N,7N
E.5N,3N
0
2
2
2
2
2
0
0