What can we say about the rock as it falls to earth?
a) it accelerates as it falls.
b) it falls at a constant rate of speed.
c) it is at a constant velocity as it falls.
d) it accelerates until it reaches a peak velocity, then decelerates.
7)
which object is accelerating?
a) a lamp standing motionless on a desk.
b) a ball on a string whirled in a circle at a constant speed.
c) a car driving straight along a highway at a constant speed.
d) a humming bird hovering perfectly still in front of a flower.
8)
the difference between speed and velocity is that
a) speed is a vector and requires a direction.
b) speed is a vector and requires a magnitude.
c) velocity is a vector and requires a direction.
d) velocity is a vector and requires a magnitude.
9)
a unit of length in the metric system is the
a) kilogram.
b) kilometer.
c) liter.
d) milliliter.
10)
which car is accelerating?
a) a car that is unmoving
b) a car that rounds a curve at a constant speed
c) a car that travels in straight line at a constant speed
d) a car that is set to a constant speed of 60 miles per hour
11)
a car starts from rest at a stop light and reaches 20 m/s in 3.5 s. determine the acceleration of the car.
a) 3.5
m
s2
b) 5.7
m
s2
c) 20
m
s2
d) 70
m
s2
12)
you own a high speed digital camera that can take a picture every 0.5 seconds. you decide to take a picture every 0.5 seconds of your physics teacher as she drops a watermelon off the top of the school. after you develop and analyze the pictures, you realize that the distance the watermelon falls from the teacher in each new picture is
a) the same in each picture.
b) gradually less in each picture.
c) gradually more in each picture.
d) proportional to the mass of the watermelon.
13)
while running around the track at school, milt notices that he runs due east on the 100m homestretch and due west on the 100m backstretch. to train for the 800m event, he runs both the 100m homestretch and the 100m backstretch in 12.2 seconds. how do milt's velocities on the homestretch and backstretch compare?
a) the homestretch and backstretch have velocities with the same magnitude only.
b) the backstretch velocity is greater in magnitude than the homestretch velocity.
c) the home stretch velocity is greater in magnitude than the backstretch velocity.
d) the homestretch and the backstretch have velocities with the same direction and magnitude.
14)
consider the average speed of a runner who jogs around a track four times. the distance (400m) remains constant for each lap. however, each lap is run 5 seconds slower than the first. the time for each lap increases. the average speed for each lap this is an example of a(n) relationship.
a) increases, direct
b) decreases, direct
c) increases, inverse
d) decreases, inverse