Physics Midterm

Which point is nearest the x axis?

(5, -2)

A stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12 m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 5.6 s. What is the height of the cliff? (g = 9.8 m/s^2 and air resistance negligible)

120 m

Human reaction time is usually about .20 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the rule to fall before you catch it? The nearest value is:

20 cm

A student adds two vectors with magnitudes of 200 and 40. Which of the following is the only possible choice for the magnitude of the resultant?

200

A rock is thrown straight up with an initial velocity of 24.5 m/s. What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s^2)

30.6 m

A drag racer starts from rest and accelerates at 10 m/s^2 for the entire distance of 400 m (1/4 mile). What is the velocity of the race car at the end of the run?

89 m/s

Jeff throws a ball straight up. For which situation is the vertical velocity zero?

At the top

An object is dropped from a height. Once it is moving, which of the following statements is true, at least at one point?

Its velocity is never equal to its acceleration

In mechanics, physicists use three basic quantities to derive additional quantities. Mass is one of the three quantities, what are the other two?

Length and Time

The value of an object's acceleration may be characterized in equivalent words by which of the following?

Rate of change of velocity

If the displacement of an object is given in SI units by Δx = -3t + 4t^2 , at t=2 s its velocity and acceleration are, respectively:

positive, positive.

Displacement is which of the following types of quantities?

vector

A cheetah can run at approximately 100 km/hr and a gazelle at 80 km/hr. If both animals are running at full speed, with the gazelle at 70 m ahead, how long before the cheetah catches its prey?

12.6 s

The first displacement is 6 m and the second displacement is 3 m. They cannot add together to give a total displacement of:

2 m

A right triangle has sides 5.0 m, 12 m, and 13 m. The smallest angle of this triangle is nearest (degrees):

23°

An object, initially moving in the negative x-direction, is subjected to a change in velocity in the positive y-direction. If the resulting velocity vector is drawn from the origin, into which quadrant does this vector point?

2nd

A truck moves 70 m east, then moves 120 m west, and finally moves east again a distance of 90 m. If east is chosen as the positive direction, what is the truck's resultant displacement?

40 m

A rifle is aimed horizontally toward the center of a target 100 m away. If the bullet strikes 10 cm below the center, what was the velocity of the bullet? (ignore air friction)

700 m/s

Since 1967 the standard definition for the second has been based on which of the following?

Characteristics frequency of the cesium-133 atom

Consider the sine of any angle between 30° and 40°. If the angle were doubled, what would happen to the sine of the angle?

It would increase but be less than double

Which of the following is not a vector quality? a. velocity b. temperature c. acceleration d. displacement

Temperature

A change in physical quantity w having initial value wi and final value wf is given by which of the following?

wi - wf

For which of the values below is x>x^3?

x = -1.5

A ball is rolled horizontally off a table with an initial speed of .24 m/s. A stopwatch measures the ball's trajectory time from table to the floor to be .30 s. How far away from the table does the ball land? (g = 9.8 m/s^2 and air resistance negligible)

.072 m

A ball is rolled horizontally off a table with an initial speed of .24 m/s. A stopwatch measures the ball's trajectory time from table to the floor to be .30 s. What is the height of the table? (g = 9.8 m/s^2 and air resistance negligible)

.44 m

An object moves 20 m east in 30 s and then returns to its starting point taking an additional 50 s. If west is chosen as the positive direction, what is the sign associated with the average velocity of the object?

0 (no sign)

A cereal box has the dimensions of 0.19 m x 0.28 m x 0.070 m. If there are 3.28 feet per meter, then what is the volume of the box in cubic feet?

0.13 cubic feet

A track star in the broad jump goes into the jump at 12 m/s and launches himself at 20 degrees above the horizontal. How long is he in the air before returning to Earth? (g = 9.8 m/s^2)

0.84 s

if φ=90° - θ, what is the value of sin^2 φ + sin^2 θ?

1

A baseball is released at rest from the top of the Washington Monument. It hits the ground after falling for 6.0 s. What was the height from which the ball was dropped? (g=9.8 m/s^2 and assume air resistance is negligible)

1.8 x 10^2

If point A is located at coordinates (5, 3) and point B is located at coordinates (-3, 9), what is the distance from A to B if the units of the coordinated system are meters?

10 m

A vehicle designed to operate on a drag strip accelerates from zero to 30 m/s while undergoing a straight line path displacement of 45 m. What is the vehicle's acceleration of its value may be assumed to be constant?

10 m/s^2

Vector A is 3.0 units in length and points along the positive x axis; vector B is 4.0 units in length and points along a direction 150 degrees from the positive x-axis. What is the direction of the resultant with respect to the positive x-axis?

103 degrees

The prefixes which are abbreviated p, n, and G represent which of the following?

10^-12 10^-9 and 10^9

A physics class in a large lecture hall has 150 students. The total mass of the students is about

10^4

The ratio M/m of the prefixes M and m has what value?

10^9

An automobile driver puts on the brakes and decelerates from 30.0 m/s to zero in 10 s. What distance does the car travel?

150 m

A ball is pushed with an initial velocity of 4.0 m/s. The ball rolls down a hill with a constant acceleration of 1.6 m/s^2. The ball reaches the bottom of the hill in 8.0 s. What is the ball's velocity at the bottom of the hill?

17 m/s

Each edge of a cube has a length of 25.4 cm. What is the length of a diagonal of the cube going through the center of the cube?

17.3 in

The distance to the Andromeda Galaxy is estimated at about 2 x 10^6 light years. A light year is the distance traveled by light in one year; if the speed of light is 3 x 10^8 m/s, about how far is it from our galaxy to Andromeda? (1 year = 3.15 x 10^7 s)

2 x 10^22 m

Vector A is 3.0 units in length and points along the positive x axis; vector B is 4.0 units in length and points along a direction 150 degrees from the positive x-axis. What is the magnitude of the resultant when vectors A and B are added?

2.1

A Cessna aircraft has a lift-off speed of 120 km/hr. What minimum constant acceleration does this require if the aircraft is to be airborne after a take-off run of 240 m?

2.31 m/s^2

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is the average velocity?

2.5 m/s

Wiley Coyote has missed the elusive road runner once again. This time, he leaves the edge of the cliff at 50.0 m/s horizontal velocity. If the canyon is 100 m deep, how far from his starting point at the edge of the cliff does the coyote land?

226 m

A triangle has sides of length 7.0 cm and 25 cm. If the triangle is a right triangle, which of the following could be the length of the third side?

24 cm

A furlong is a distance 220 yards. A fortnight is a time period of two weeks. A race horse is running at a speed of 5.00 yards per second. What is his speed in furlongs per fortnight?

27 500 furlongs/fortnight

Gwen releases a rock at rest from the top of a 40-m tower. If g = 9.8 m/s^2 and air resistance is negligible, what is the speed of the rock as it hits the ground?

28 m/s

Arvin the Ant is on a picnic table. He travels 30 cm eastward, then 25 cm northward, and finally 15 cm westward. What is the magnitude of Arvin's net displacement?

29 cm

Vectors A, B, and C have magnitudes 6, 11, and 20. When these vectors are added, what is the least possible magnitude of their resultant?

3

One year is about ___ seconds while one day is exactly ___ seconds.

3.16 x 10^7 86,400

A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100 km'hr in 8.00 s. If so, what is the acceleration? (Hint: First convert speed to m/s)

3.47 m/s^2

A high fountain of water is in the center of a circular pool of water. You walk the circumference of the pool and measure it to be 150 m. You then stand at the edge of the pool and use a protractor to gauge the angle of elevation at the top of the fountain. It is 55°. How high is the fountain?

34 m

When NASA was communicating with astronauts on the moon, the time from sending on the Earth to receiving on the moon was 1.28 s. Find the distance from Earth to the moon. (The speed of radio waves is 3.00 x 10^8 m/s)

384 000 km

A quarterback takes the ball from the line of scrimmage, runs backward for 10 yards, then sideways parallel to the line of scrimmage for 15 yards. He then throws a 50 yard forward pass straight downfield perpendicular to the line of scrimmage. The receiver is tackled immediately. How far is the football displaced from its original position?

43 yards

A rock is thrown straight down with an initial velocity of 14.5 m/s from a cliff. What is the rocks's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s^2)

49 m

A bird, accelerating from rest at a constant rate, experiences a displacement of 28 m in 11 s. What is the final velocity after 11 s?

5.1 m/s

On planet Z, the standard unit of length is the foose. Ann the Astronaut is 5.90 feet tall on earth. She lands on planet Z and is measured to be 94 foosi tall. Her partner Rachael is 88 foosi tall. How tall is Rachael on Earth?

5.5 feet

A baseball player can jump 1.6 m off the hardwood floor. With what upward velocity did he leave the floor?

5.6 m/s

A stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12 m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 5.6 s. How far out from the cliff's edge does the stone travel horizontally? (g = 9.8 m/s^2 and air resistance negligible)

58 m

Arvin the ant travels 30 cm eastward, then 25 cm northward, and finally 15 cm westward. What is Arvin's direction of displacement with respect to his original position?

59 degrees N of E

A helicopter is traveling at 40 m/s at a constant altitude of 100 m over a level field. If a wheel falls off the helicopter, with what speed will it hit the ground? (g = 9.8 m/s^2 and air resistance negligible)

60 m/s

A water rocket, launched from the ground, rises vertically with acceleration of 30 m/s^2 for 1.0 s when it runs out of "fuel." Disregarding air resistance, how high will the rocket rise?

61 m

The following force vectors act on an object: i) 50.0 newtons at 45 degrees north of east and ii) 25 newtons at 30 degrees south of east. Which of the following represents the magnitude of the resultant and its angle relative to the easterly direction?

61.4 newtons 21.8 degrees

A railroad train travels forward along a straight track at 80 m/s for 1,000 m and then travels at 50 m/s for the next 1,000 m. What is the average velocity?

61.5 m/s

Find the resultant of the following two vectors i) 50 units due east and ii) 100 units 30 degrees north of west

62 units 54 degrees north of west

A cart is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.0 m/s^2. What is the magnitude of the cart's displacement during the first 6.0 s of its motion?

66 m

John throws a baseball from the outfield from shoulder height, at an initial velocity of 29.4 m/s at an initial angle of 30.0 with respect to the horizontal. The ball is in its trajectory for a total interval of 3 s before the third baseman catches it at an equal shoulder-height level. (Assume air resistance negligible). What is the ball's horizontal displacement?

76.4 m

A taxicab moves five blocks due north, five blocks due east, and another two blocks due north. Assume all blocks are of equal size. What is the magnitude of the taxi's displacement, start to finish?

8.6 blocks

A ball is launched from ground level at 30 m/s at an angle of 35 degrees above the horizontal. How far does it go before it is at ground level again?

86 m

A train slowly climbs a 500-m mountain track which is at an angle of 10° with respect to the horizontal. How much altitude does it gain?

86.8 m

A string attached to an airborne kite is maintained at an angle of 40 degrees with the horizontal. If a total of 120 m of string is reeled in while bringing the kite back to the ground, what is the horizontal displacement of the kite in the process? (Assume the kite string doesn't sag)

92 m

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at an equal shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? (air resistance is negligible)

Acceleration is constant during entire trajectory

Two projectiles are launched at 100 m/s, the angle of elevation for the first being 30 degrees and for the second 60 degrees. Which of the following statements is false?

All of the above statements are false

A baseball catcher throws a ball vertically upward and catches it in the same spot when it returns to his mitt. At what point in the ball's path does it experience zero velocity and non-zero acceleration at the same time?

At the top of its trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at an equal shoulder level) by the catcher. At what point does the magnitude of the vertical component of velocity have its minimum value? (air resistance is negligible)

At the top of the trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at an equal shoulder level) by the catcher. At what point is the ball's speed at a minimum? (air resistance is negligible)

At the top of the trajectory

Two objects of different mass are released simultaneously from the top of a 20-m tower and fall to the ground. If air resistance is negligible, which statement best applies?

Both objects hit the ground together

In a 2-dimensional Cartesian coordinate system the x-component of a given vector is equal to that vector's magnitude multiplied by which trigonometric function, with respect to the angle between vector and x-axis?

Cosine

In a 2-dimensional Cartesian coordinate system the y-component of a given vector is equal to that vector's magnitude multiplied by which trigonometric function, with respect to the angle between vector and y-axis?

Cosine

In a 2-dimensional Cartesian coordinate system the x-component of a given vector is known, and the angle between vector and x-axis is known. Which operation is used to calculate the magnitude of the vector? (taken with respect to the x-component)

Dividing by cosine

In the case of constant acceleration, the average velocity equals the instantaneous velocity:

Half-way through the time interval

In one-dimensional motion where the direction is indicated by a plus or minus sign, the average velocity of an object has which of the following properties?

It can can be positive, negative, or zero

In one-dimensional motion, the average speed of an object that moves from one place to another and then back to its original place has which of the following properties?

It is positive

A ball is thrown vertically upwards at 19.6 m/s. For its complete trip (up and back down to the starting position), its average velocity is:

Not given

Since 1983 the standard meter has been defined in terms of which of the following?

The distance light travels in a certain fraction of a second

Four vectors all have the same magnitude. Vector 1 is at 30 degrees, Vector 2 is at 135 degrees, vector 3 is at 240 degrees, and vector 4 is at 315 degrees. Which vector has the greatest magnitude x-component and which vector has the greatest magnitude y-component?

Vector 1, Vector 3

Vector 1 is 7 units long and is at 70 degrees. Vector 2 is 5 units long and at 225 degrees. Vector 3 is 3 units long and is at 150 degrees. Which vector has equal magnitude components?

Vector 2

Starting from rest, a car accelerates down a straight road with constant acceleration a1 from a time t1, then the acceleration is changed to a different constant value a2 for an additional time t2. The total elapsed time is t1 + t2. Can the equations of kinematics be used to find the total distance traveled?

Yes, break the problem into 2 problems, one with the conditions for the first time interval and the other with the conditions for the second time interval, noting that for the second time interval the initial velocity is that from the end of the first time interval. When done, add the distances from each of the time intervals.

when we add displacement vector to another displacement vector, the result is

another displacement

When we subtract a velocity vector from another velocity vector, the result is:

another velocity

Note the expression: y = x^2. Which statement is most consistent with this expression?

if x doubles, then y quadruples

Note the expression: y = A/x^3. Which statement is most consistent with this expression

if x is halved, y is multiplied by eight

The speed of a boat is often given in knots. If a speed of 5 knots were expressed in the SI system of units, the units would be:

m/s

Vector A is 3 m long and vector B is 4 m long. The length of the sum of the vectors must be

some value from 1 m to 7 m

Which type of quantity is characterized by both magnitude and direction?

vector

Which of the following is an example of vector quantity?

velocity