Physical Science, Chapter 11
A cheetah can accelerate at up to 6.0 m/s2. How long does it take for a cheetah to speed up from 10.5 m/s to 12.2 m/s?
.28 s
On a bus traveling north at 20.0 m/s, a child stands up and walks toward the back of the bus at 1.3 m/s. What is the child's resultant velocity?
18.7 m/s North
Moving from 0 m/s to 25 m/s in 8.0 s equals an average acceleration of ?
3.1 m/s2
The average speed of a runner who runs 500.0 m in 1.6 minutes is...
312 m/s
A pitcher throws a baseball to home plate, a distance of 60.5 ft. The ball reaches home plate in 0.63 s. What is the velocity of the ball?
96 ft/s toward home plate
Which is an example of balanced forces acting on an object?
A leaf lying on the grass
Which of the following best illustrates balanced forces?
A stretched rubber band being held between two hands
Which of the following requires friction?
All of the above
Which straight-line acceleration indicates an increase in speed?
All of the above
The distance traveled by an object divided by the time it takes to travel that distance is called...
Average speed
If the net force on an object is zero than the object has ?
Balanced forces
In order to determine speed, you must know...
Both time and distance
AN airplane is flying at 635 mi/h at an altitude of 35,000 ft. It is currently over Kansas and is approximately 16 minutes ahead of schedule. What is its velocity?
Can't be determined without further information.
When centripetal acceleration occurs, an object ?
Changes direction
Which is an example of helpful friction?
Come back too me!!!
When velocity changes by the same amount over each time interval, acceleration is...
Constant
Displacement must always indicate ?
Direction
The difference between speed and velocity is that velocity includes...
Direction
Average speed can be represented by the mathematical expression...
Distance/time
A car is parked on a hill. In order to keep the car from rolling downhill, how great must the static friction acting on the car be?
Equal to the force that is pulling the car downhill
The equation for finding average acceleration for straight-line motion is ?
Final velocity - initial velocity/time
On a distance vs. time graph, the line of an object at rest is a...
Flat line with a slope of zero
Friction is defined as the...
Force that opposes motion between two touching surfaces
The force of gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force are considered....
Fundamental forces.
An object that changes position relative to a reference point is...
In motion
Which of the following speeds is the most accurate?
Incorrect answer: 100 miles per hour
A car moving at an average speed of 55.0 mi/h for 4.25 h has traveled...
Incorrect answer: 13 mi. Possible answer: 233.75
A cyclist is traveling at an initial speed of 10.0 m/s. She accelerates at a rate of 0.500 m/s2. What is her final speed after 9.0 s?
Incorrect answer: 14.5 m/s2
Which of the following statements is true?
Incorrect answer: Friction can exist between two objects even when they are not in contact.
Peter runs in a constant direction on a straight road. The velocity vs. time graph of Peter's motion shows a straight line with a negative slope. What does the line tell you about Peter's speed?
It is decreasing
In order to increase a car's speed, the force pushing if forward must be...
Kinetic friction
Force is a quantity made up of...
Magnitude and direction
When an object slows down, its acceleration is...
Negative
What happens when a car slows down and velocity changes?
Negative acceleration
The combination of all of the forces acting on an object is called the...
Net force
Which is an example of static friction?
Pushing a box that is at rest
If the net force acting on a stationary object is zero, then the object will...
Remain at rest
Which is not an example of sliding friction?
Rolling a ball across a desk
How can the friction on a water slide be reduced?
Run a constant stream of water down the slide
On a speed-time graph, a line with a negative slope indicates that the object is ?
Slowing down
When the motion of an object is shown by a straight line on a distance vs. time graph with distance on the y-axis, the slope of the line is the ?
Speed
The friction between objects that are stationary is called...
Static friction
On a speed vs. time graph, constant acceleration is represented by a...
Straight line
Net force is...
The combination of all the forces action on an object
On a distance vs. time graph of an object's motion, distance is usually ?
The dependent variable
An object is in motion when...
The object changes position relative to a frame of reference
An object is in motion when...
The object changes position relative to a stationary reference point.
A force is continuously applied to an object, causing it to accelerate. After a period of time, however, the object stops accelerating. What conclusion can be drawn?
The object is experiencing some kind of friction
On a velocity vs. time graph, what shows the value of the acceleration?
The slope of the line
Acceleration is defined as the change in velocity divided by ...
Time
A game of tug-of-war is an example of...
Unbalanced forces
A tug-of-war that results in one team pulling the other across the line is an example of ?
Unbalanced forces
The Of an object consists of its speed and direction...
Velocity
An object experiencing balanced forces...
has a net force of zero
The SI unit for speed is ?
m/s