Physics Final

A large school district has 300 school buses. If each school bus is used 3.0 hours each day, the average speed of the school buses is 15 mi/h, and the fuel economy of the buses is 10 mi/gal. How much does it cost to run these buses for 22 school days if gasoline costs $4.10 a gallon?

$120,000

On an aircraft carrier, a jet can be catapulted from 0 to 200 km/h in 2.1 s . If the average force exerted by the catapult is 9.15×105 N , what is the mass of the jet? Express your answer to three significant figures and include the appropriate units.

- 200k/m = 55.55 m/s - 55.55/ 2.1 = 26.45 - 9.15 x 10 ^5 / 26.45 = 34587 34,587 kg

Question 16 options: Vector A⃗ has a magnitude of 50 km and points in the positive x direction. A second vector, B⃗ , has a magnitude of 120 km and points at an angle of 70∘ below the x axis. Which vector has the greater x component. Which vector has the greater y component? Consider the sign of the components.

- vector A - vector A

What is the velocity of an object that moves from 70 m to 65 m in 12 s ? Express your answer to two sig figs.

-0.42

Graphs A truck moves as shown by the velocity-time graph below. Find the average acceleration of the truck during period C. Express your answer to two significant figures. Use the form XX m/s^2 to indicate acceleration

-0.5 m/s^2

What is the velocity of an object that moves from 73 m to 65 m in 12 s ? Express your answer to two sig figs.

-0.67

A car moves with an initial velocity of 29.5 m/s due north. Find the velocity of the car after 7.2 s if its acceleration is 4.2m/s2 due south.

-0.7 m/s

Your 1,650-kg car pulls a 520-kg trailer away from a stoplight with an acceleration of 1.5-m/s2. What is the net force acting on the car?

-2,475 N

A 55-kg baseball player slides into third base with an initial speed of 4.6 m/s. If the coefficient of kinetic friction between the player and the ground is 0.38, what is the player's acceleration? (Hint: watch your sign) Express your answer to three significant figures.

-3.73 m/s^2

A car with an initial velocity of 13.9 m/s comes to rest in 2.9 s . What is the car's average acceleration during braking? Give both magnitude and sign.

-4.8 m/s^2

A block weighing 200 N is pushed along a surface. If it takes 80 N to get the block moving and 40 N to keep the block moving at a constant velocity, what are the coefficients of friction μs and μk?

.40 .20

A block weighing 200 N is pushed along a surface. If it takes 80 N to get the block moving and 40 N to keep the block moving at a constant velocity, what are the coefficients of friction μs and μk? Put μs in the first block and μk in the second block.

.40 .20

A severe storm on January 10, 1992, near the Aleutian Islands, caused a cargo ship to spill 29,000 rubber ducks and other bath toys into the ocean. Ten months later hundreds of rubber ducks began to appear along the shoreline near Sitka, Alaska, roughly 2600 km away. What was the approximate average speed, in meters per second (m/s), of the ocean current that carried the ducks to shore? (Rubber ducks from the same spill began to appear on the coast of Maine in July 2003.) Use an average month length of 30 days.

0.100 m/s

A person on horseback moves according to the velocity-time graph shown in the graph below. Find the average acceleration of the horse and rider for segment A of the motion. Express your number to two significant figures and include the unit. (i.e. m/s^2)

0.20 m/s^2

A 89-kg sprinter wishes to accelerate from rest to a speed of 12.2 in a distance of 30 m. (a) What coefficient of static friction is required between the sprinter's shoes and the track?

0.252

A racket ball is struck in such a way that it leaves the racket with a speed of 4.79 m/s in the horizontal direction. When the ball hits the court, it is a horizontal distance of 1.21 m from the racket. Round your answer to three significant figures and include the unit.

0.313 m

A 400-gram package lying on a horizontal surface is attached to a horizontal string which passes over a smooth pulley. When a mass of 200 grams is attached to the other end of the string, the package is on the point of moving. Find μs, the coefficient of static friction. Round to two sig figs.

0.5

A car begins to slow down as it approaches a red light. (a) If its mass is 6,140 kg and the net braking force is f 3,820 N, what is the magnitude of the cars acceleration? (Note it will be positive). Round to two places after the decimal.

0.62 m/s^2

The length and width of a rectangle are 1.125 m and 0.606 m, respectively. Multiplying, your calculator gives the product as 0.68175. Rounding properly to the correct number of significant figures, the area of the rectangle should be written as

0.682 m2

At the bow of a ship on a stormy sea, a crew member conducts an experiment by standing on a bathroom scale. In calm waters, the scale reads 755 N . During the storm, the crew member observer a maximum reading of 820 N and a minimum reading of 540 N .

0.84 m/s^2

Two golf carts move in a straight line with the following equations of motion: x1 = -16 m + 14.0t x2 = 14 m + -9.2t At what time do the golf carats collide? Express your answer to three significant figures and include the unit

1.29s

What is the difference between 103.5 and 102.24 expressed to the correct number of significant figures?

1.3

Two golf carts move in a straight line with the following equations of motion: x1 = -16 m + 13.7t x2 = 14 m + -8.4t At what time do the bumper cars collide? Express your answer to three significant figures and include the unit

1.36 s

A spherical fruit has a radius of 3.23 cm. What is the volume of the fruit in cubic meters? The equation for a sphere is 4/3 pi r^3

1.41 ´ 10-4 m3

The equation of motion for a float in a parade is x = -9.5 m + (5.9m/s)t Round answer to the hundredth of a second At what time is the float at x = 0?

1.61 s

If you are 5'10'' tall, what is your height in meters? (2.54 cm = 1.00 in.)

1.8 m

Three forces of magnitudes F1=4.0N, F2=6.0N, and F3=8.0N are applied to a block of mass m=2.0kg, initially at rest, at angles shown on the diagram. In this problem, you will determine the resultant (net) force by combining the three individual force vectors. All angles should be measured counterclockwise from the positive x axis (i.e., all angles are positive). Round to three sig figs and include the unit

1.83 N

Britta Steffen of Germany set the women's Olympic record for the 100-m freestyle swim with a time of 53.12 s. What was her average speed?

1.88 m/s1.36

A block is on an incline with an inclination angle of 18 degrees. The normal force on the block has a magnitude of 112.3 Newtons. What is the mass of the block? Use 9.8 for acceleration of gravity and round to 3 sig figs.

10.9 kg

You jog at 9.50 km/ h for 8.00 km; then you jump into a car and ride an additional 13.9 km for 1 more hour. What is your average speed over the entire trip?

11.9 m/s

In gym class you run 22 m horizontally, then climb a rope vertically for 5.4 m . What is the angle of your total displacement, as measured from the horizontal? Round to the nearest whole degree and add the word 'degrees'

14 degrees

Your car gets 34.7 mi/gal on a vacation trip in the U.S. If you were figuring your mileage in Europe, how many km/L did it get? (3.79 L = 1.00 gal; 1.00 mi = 1.61 km)

14.7 km/L

A marathon runner runs at a steady 15 km/hr. When the runner is 7.5 km from the finish, a bird begins flying from the runner to the finish at 30 km/hr. When the bird reaches the finish line, it turns around and flies back to the runner, and then turns around again, repeating the back-and-forth trips until the runner reaches the finish line. How many kilometers does the bird travel? Round to two sig figs and include the unit

15km

Two forces, F⃗1 and F⃗2, act at a point, as shown in the picture. F⃗1 has a magnitude of 9.00 N and is directed at an angle of α = 24∘ above the negative x axis in the second quadrant. F⃗2 has a magnitude of 12 N and is directed at an angle of β = 25∘ below the negative x axis in the third quadrant.

17.03

As an airplane taxies on the runway with a speed of 19.3 m/s , a flight attendant walks toward the tail of the plane with a speed of 1.22 m/s. Round to the tenth of a m/s

18.08 m/s

A golfer sends the ball over a 3.00 m-high tree that is 14.0 m away. The initial velocity is 13.5 m/s. (a) What is the maximum range of the golf ball? express your answer to three significant figures and include the unit

18.6 m

Two forces, F⃗1 and F⃗2, act at a point, as shown in the picture. F⃗1 has a magnitude of 9.00 N and is directed at an angle of α = 28∘ above the negative x axis in the second quadrant. F⃗2 has a magnitude of 12 N and is directed at an angle of β = 23∘ below the negative x axis in the third quadrant.

19.63

A skier starts from rest and accelerates down a slope at 3.7m/s2 . How much time is required for the skier to reach a speed of 8.1 m/s ?

2.2 s

A person places a cup of coffee on the roof of her car while she dashes back into the house for a forgotten item. When she returns to the car, she hops in and takes off with the coffee cup still on the roof. If the coefficient of static friction between the coffee cup and the roof of the car is 0.24, what is the maximum acceleration the car can have without causing the cup to slide? Ignore the effects of air resistance. Round to two sig figs.

2.4 m/s^2

You are driving up an inclined road. After 3.2 km you notice a roadside sign that indicates that your elevation has increased by 160 m. What is the angle of the road above the horizontal? round to the nearest tenth of a degree and add the word 'degrees'

2.8, 2.9 degrees

As an airplane taxies on the runway with a speed of 23.5 m/s , a flight attendant walks toward the tail of the plane with a speed of 1.22 m/s. What is his speed relative to the ground? Round to the tenth of a m/s.

22.3 m/s

A car moves with an initial velocity of 14.0 m/s due north. Find the velocity of the car after 5.1 s if its acceleration is 1.9 m/s2 due north.

23.69 m/s

The graph in the figure shows the position of a particle as it travels along the x-axis. At what value of t is the speed of the particle equal to 0 m/s?

3 s

The quantity 0.00325 x 10-8 cm is equivalent to

3.25 x 10-10 mm

A gymnast of mass 41 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.8m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast slides down the rope with a downward acceleration of magnitude 1.4m/s2 .

344 N

The column of Trajan, erected in Rome in 106-113 A.D., is 125 feet tall. What is its height in centimeters? (2.54 cm = 1.00 in.)

3810

A gymnast of mass 39 kg hangs from a vertical rope attached to the ceiling. You can ignore the weight of the rope and assume that the rope does not stretch. Use the value 9.8m/s2 for the acceleration of gravity. Calculate the tension T in the rope if the gymnast climbs up the rope with an upward acceleration of magnitude 1.7m/s2 . Express your answer in newtons.

449 N

Vector A has a magnitude of 27 m and points in a direction 32 degree(s) above the positive x axis. Vector B has a magnitude of 35 m and points in a direction 55 degree(s) below the positive x axis. Using the component method of vector addition, find the magnitude of vector C⃗ , where C⃗ =A⃗ +B⃗ .

45.3

The great, gray-green, greasy Zambezi River flows over Victoria Falls in south central Africa. The falls are approximately 109 m high. If the river is flowing horizontally at 3.09 m/s just before going over the falls, what is the speed of the water when it hits the bottom? Assume the water is in free fall as it drops. Round to one place past the decimal and include the units.

46.3 m /s

A soccer ball rests on the field at the location x = 5.0 m. Two players run along the same straight line toward the ball. Their equations of motion are as follows: x1 = -.1.0 m + (4.6 m/s )t x2 = -8.0 m + (3 m/s )t At what time does one player pass the other player? Express your answer to three significant figures and include the appropriate units.

5.38s

A ferry approaches shore, moving north with a speed of 7.5 m/s relative to the dock. A person on the ferry walks from one side of the ferry to the other, moving east with a speed of 1.0 m/s relative to the ferry. What is the speed of the person relative to the ground? Round to 2 significant figures

7.56 m/s

A diver runs horizontally off the end of a diving board with an initial speed of 1.90 m/s. (a) If the diving board is 3.00 m m above the water, what is the diver's speed just before she enters the water? Round to three significant figures

7.90 m/s

Vector A⃗ points in the positive y direction and has a magnitude of 12 m. Vector B⃗ has a magnitude of 33 m and points in the negative x direction. Find the direction of A⃗ + B⃗ . Write out the word degrees and indicate the direction. (For example 33 degrees E of N)

70 degrees W of N

Your 1,590-kg car pulls a 510-kg trailer away from a stoplight with an acceleration of 1.4-m/s2. What is the net force exerted by the car on the trailer?

714 N

While you are exploring Cretaceous Park, you notice a friendly little microraptor flies 27 m [42°E of N] and then 25 m [11° E of S] Use the component method to determine the microraptor's total displacement. (Include the angle in the answer

75 m ; 54 degrees E of S

World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s2. How much horizontal force F must a sprinter of mass 51 kg exert on the starting blocks to produce this acceleration?

765 N

A block of mass " role="presentation">8.58.58.5 kilograms is set on a frictionless incline with an inclination angle of 20 degrees. What is the magnitude of the normal force on the block? Round to 3 sig figs and use 9.8 as the acceleration of gravity.

78.3 N

Question 16 options: A baseball "diamond" (the figure) is a square with sides 90 ft in length. The positive x axis points from home plate to first base, and the positive y axis points from home plate to third base. Find the displacement vector of a base runner who has just hit a double. What is the value of the x vector (Include the unit after a space) What is the value of the y vector. Include the unit after a space What is the total displacement of the runner? (Round to the nearest whole number and add a space and then the unit)

90ft 90ft 127ft

What is the result, expressed to the proper number of significant figures, of adding 23.4 to 91.237 and then subtracting 23.4?

91.2

A jet ski travels across a river going 9.5 m/s at an angle of 20.0∘ upstream, what is the speed of the Jet Ski relative to the water? (Note: Angles are measured relative to the x axis shown in the figure.) Round to two sig figs and include the unit

Answer:8.9 m/s

Which of the following equations correctly expresses the relation between vectors A⃗ , B⃗ , and C⃗ shown in the figure?

A⃗ +B⃗ +C⃗ =0

If the velocity of an object is zero at one instant, what is true about the acceleration of that object? (There could be more than one correct choice.)

The acceleration could be positive. The acceleration could be negative The acceleration could be zero.

A rock from a volcanic eruption is launched straight up into the air with no appreciable air resistance. Which one of the following statements about this rock while it is in the air is correct?

The acceleration is downward at all points in the motion.

Suppose that an object is moving with a constant velocity. Which statement concerning its acceleration must be correct?

The acceleration is equal to zero.

Suppose that a car traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct?

The acceleration is toward the east.

The same net force is applied to two different objects. The second object has twice the mass of the first object. Compare the acceleration of the two objects.

The acceleration of object 1 is twice the acceleration of object 2.

The figure shows the velocity versus time graph for a car driving on a straight road. Which of the following best describes the acceleration of the car?

The acceleration of the car is positive and decreasing.

Suppose that an object travels from one point in space to another. Make a comparison between the magnitude of the displacement and the distance traveled by this object.

The displacement is either less than or equal to the distance traveled

A packing crate is sitting at rest on an inclined loading ramp. How does the magnitude of the force of static friction compare to the other forces acting on the crate?

The magnitude of the force of static friction is equal to the magnitude of the component of the weight of the crate parallel to the inclined ramp.

A man attempts to pick up his suitcase of weight ws by pulling straight up on the handle. However, he is unable to lift the suitcase from the floor. Which statement about the magnitude of the normal force n acting on the suitcase is true during the time that the man pulls upward on the suitcase?

The magnitude of the normal force is equal to the magnitude of the weight of the suitcase minus the magnitude of the force of the pull.

A man attempts to pick up his suitcase of weight Ws by pulling straight up on the handle. However, he is unable to lift the suitcase from the floor. Assume that the man of weight Wm is tired and decides to sit on his suitcase.

The magnitude of the normal force is equal to the sum of the magnitude of the man's weight and the magnitude of the suitcase's weight.

A man attempts to pick up his suitcase of weight ws by pulling straight up on the handle. However, he is unable to lift the suitcase from the floor. Assume that the man of weight wm is tired and decides to sit on his suitcase.

The magnitude of the normal force is equal to the sum of the magnitude of the man's weight and the magnitude of the suitcase's weight.

You push two identical bricks across a tabletop with constant speed, v, as shown in the figure . In case 1 you place the bricks end to end; in case 2 you stack the bricks one on top of the other. Choose the best explanation from among the following:

The normal force is the same in the two cases, and friction is independent of surface area.

Consider a deer that runs from point A to point B. The distance the deer runs can be greater than the magnitude of its displacement, but the magnitude of the displacement can never be greater than the distance it runs.

True

As part of a physics experiment, you stand on a bathroom scale in an elevator. Though your normal weight is 570 N , the scale at the moment reads 730 N . What is the direction of acceleration?

Upward

When is the average velocity of an object equal to the instantaneous velocity?

When the velocity is constant

An object is moving with constant non-zero acceleration in the +x direction. The velocity versus time graph of this object is

a straight line making an angle with the time axis.

The slope of a velocity versus time graph gives

acceleration.

If the position versus time graph of an object is a horizontal line, the object is

at rest

An auto manufacturer advertises that their car can go "from zero to sixty in eight seconds." This is a description of what characteristic of the car's motion?

average acceleration

You push two identical bricks across a tabletop with constant speed, v, as shown in the figure . In case 1 you place the bricks end to end; in case 2 you stack the bricks one on top of the other. Is the force of kinetic friction in case 1 greater than, less than, or equal to the force of kinetic friction in case 2?

equal to

Two drivers traveling side by side at the same speed suddenly see a deer in the road ahead of them and begin braking. Driver 1 stops by locking up his brakes and screeching to a halt; driver 2 stops by applying her brakes just to the verge of locking, so that the wheels continue to turn until her car comes to a complete stop. All other factors being equal, is the stopping distance of driver 1 greater than, less than, or equal to the stopping distance of driver 2?

greater than

A constant force is exerted for a short time interval on a cart that is initially at rest on an air track. This force gives the cart a certain final speed. The same force is exerted for the same length of time on another cart, also initially at rest, that has twice the mass of the first one. The final speed of the heavier cart is

half

Consider the situation depicted here. A gun is aimed directly at a dangerous criminal hanging from the gutter of a building. The target is well within the gun's range, but the instant the gun is fired and the bullet moves with a speed vo, the criminal lets go and drops to the ground. What happens? The bullet

hits the criminal regardless of the value of vo.

When a ball is thrown straight up with no air resistance, the acceleration at its highest point

is downward

You drive 6.0 km at 50 km/h and then another 6.0 km at 90 km/h. Your average speed over the 12 km drive will be

less than 70 km/h.

A person standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed is the one initially thrown

neither-they both hit at the same speed

Ball A is dropped from the top of a building. One second later, ball B is dropped from the same building. Neglect air resistance. As time progresses, the difference in their speeds

remains constant.

An object is moving with constant non-zero velocity in the +x direction. The position versus time graph of this object is

straight line making an angle with the time axis.

If all forces are balanced on an object then

the object's acceleration must be zero

Refer the following figure, write the equation of motion for object A. Make sure the slope is accurate to two significant figures

x=35-8.57t