Physics fall semester final review - questions
Kevin throws a spiral to trey at an angle of 45 degrees from the horizontal. it leaves his hand with a velocity of 15 m/s. what are the vertical and horizontal components of the football's velocity
10.61 m/s and 10.61 m/s
a canon with a barrel velocity of 100 m/s launches a cannonball horizontally from a tower. neglecting air resistance, where will the cannonball be 1 second later
100 m downrange
a jogger runs 10 blocks east, 5 blocks south, and another 2 blocks east. assume all blocks are equal size. what is the magnitude of the jogger's displacement
13 blocks
convert 54 km/hr to m/s
15
a coin released at rest from the top of a tower hits the ground after falling 1.5 seconds. what is the speed of the coin as it hits the ground
15 m/s
if a car speeds up from 20 m/s to 60 m/s in 2.5 seconds, what is the car's acceleration
16 m/s
a toy car is given an initial velocity of 5 m/s and experiences a constant acceleration of 2 m/s/s. what is the final velocity after 6 s
17 m/s
a marble accelerates from rest at a constant rate and travels for a total displacement of 44 m in 20 seconds. what is the average velocity of the marble
2.2 m/s
a ball is thrown straight upward at 20 m/s. Ideally, the ball will return to the thrower's hand with a speed of
20 m/s
a skateboarder rolls 25 m down a hill that descends at an angle of 20 degrees with the horizontal. find the horizontal and vertical components of the skateboarders displacement
23.5 m and 8.55
a dolphin swims 1.85 km/hr. how far has the dolphin traveled after .6 hr.
1.1 km
suppose a small plane can fly at 200 km/hr relative to the surrounding air. suppose also that there is a 40 km/hr tailwind. how fast does the plane's shadow move across the ground
240 km/hr
if you pull horizontally on a crate with a force of 150 N and the crate does not move, the friction force must be 1150 N. Now if you pull with 250 N so that the crate slides at constant velocity, the friction force is...
250 N
a girl pulls on a 10 kg wagon with a constant force of 30 N. what is the wagons acceleration
3 m/s
A hiker travels south along a straight path for 1.5 hr with an average velocity of .75 km/hr, then travels south for 2.5 hrs with an average velocity of .9 km/hr. what is the hiker's displacement?
3.4 km to the south
convert 12 m/s to km/hr
43.2
in the absence of air resistance, the angle at which a thrown ball will go the farthest is...
45 degrees
write 54300 in sci. notation
5.43 x 10^4
a 10 N falling object encounters 4 N of air resistance. the magnitude of the net force on the object is
6 N
a duck waddles 2.5 m east and 6 m north. what are the magnitude and direction of the duck's displacement with respect to its original position
6.5 m at 67 degrees north of east
what is the mass of a person that weighs 600 N
60 kg
suppose you take a trip that covers 240 km and takes 4 hours to make. your average speed is
60 km/hr
for the winter, a duck flies 10 m/s south against a gust of wind with a velocity of 2.5 m/s. what is the resultant velocity of the duck
7.5 m/s south
write 75 x 10^4 in regular notation
750000
which of the following is a value for the acceleration of objects in free fall
9.8 m/s
a string attached to an airborne kite was maintained at an angle of 40 degrees with the ground. if 120 m of string was reeled in to return the kite back to the ground, what was the horizontal displacement of the kite
92 m
the horizontal component of a projectile's velocity is
independent of the vertical component of its velocity
the tendency of an object to maintain its state of motion
inertia
when you look at the speedometer in a moving car, you can see the car's...
instantaneous speed
how does acceleration of an object change in relation to its mass? it is...
inversely proportional
when a basketball player jumps to make a shot, once the feet are off the ground, the jumper's acceleration...
is gravity; no more, no less
what are the units for velocity
m/s
what are the unit for acceleration
m/s2
a measure of the quantity of matter is
mass
the most appropriate SI unit for measuring the length of an automobile is the
meter
at the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. which ball hits the ground first
neither- they both hit the ground at the same time
which of the following is the motion of objects moving in two dimensions under the influence of gravity
projectile motion
identify the following quantities as scalar or vector; the mass of an object, the number of leaves on a tree, wind velocity
scalar, scalar, vector
which of the following is a physical quantity that has a magnitude but no direction
scalor
which statement about the acceleration of an object is correct
the acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object
according to newtons second law, when the same force is applied to two objects of different masses,
the object with greater mass will experience a smaller acceleration and the object with less mass will experience a greater acceleration
acceleration is
the rate of change of velocity
in projectile motion, the horizontal component of a projectile's velocity is independent of
the vertical component of the velocity
what is how fast something is moving and in what direction
velocity
which of the following is an example of a vector quanity
velocity
a change in the force of gravity acting on an object will affect the objects
weight
the magnitude of the force of gravity acting on an object is...
weight
if i am traveling at a constant speed of 40 km/hr in a circle, am i accelerating
yes
the absences of air friction, the vertical component of a projectile's velocity does not change as the projectiles moves. this statement is...
always false
the law of inertia states that an object
at rest will remain at rest unless acted on by an outside force, will continue moving at the same velocity unless an outside force acts on it, will continue moving in a straight line unless an outside force acts on it, that is not moving will never move unless a force acts on it.
at what point in its path does a projectile have its minimum speed
at the top
the baseball catcher throws a ball vertically upward and catches it is the same spot as it returns to the mitt. at what point in the balls path does it experience zero velocity and nonzero acceleration at the same time
at the top of its trajectory
which of the following is the cause of an acceleration or a change in an objects motion
force
acceleration due to gravity is also called
free fall acceleration
the horizontal component of a projectile moving at constant velocity may be affected by..
friction
which of the following forces is an example of a contact force
frictional force
write 8.5 x 10^-2 in regular notation
.085
convert 245 g to kg
.245
convert 53.2 cm to m
.532
write 0.00075 in sci. notation
.75 x 10^-4
which of the following is an example of projectile motion
a bullet being fired from a gun
speed is
a measure of how fast something is moving, the distance covered per unit of time, always measured in terms of a unit of distance divided by a unit of time
what is the shape of the path of a projectile
a parabola
when something falls to the ground, it accelerates. this acceleration is called the acceleration due to gravity and is symbolized by the letter g. what is the value of g on the earths surface
about 9.8 m/s/s
if a net force is acting on an object, then the object is definitely
being accelerated
an object moves horizontally at constant speed but is subject to a vertically downward acceleration. the path of the object is
curved or parabolic
a ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. during this time, the accelerations of the ball is always...
directed downward
the acceleration produced by a net force on an object is
directly proportional to the magnitude of the net force, in the same direction as the net force, inversely proportional to the mass of the object
a ball thrown into the air at some angle between 10 degrees and 90 degrees. at the very top of the ball's path its velocity is...
entirely horizontal
an arrow is shot horizontally at a target 5 meters away with a velocity of 5 m/s. the target and bow are both 3 meters above the ground. will the arrow fall short, hit the target head on, or go above and past the target and by how much
fall short by 1.1 m.
objects that are falling toward earth moves
faster and faster
what causes a moving object to change direction
force