Unit 1 Physics

In the equation z = ct + d, z is measured in meters and t is measured in seconds. What are the dimensions (units) of c? A. s/m B. m/s C. s D. m*s E. m

B. m/s

Consider the vectors r, r1, and r2, as illustrated. Which of the following shows their correct relation? A. r= r1 - r2 B. r= r2 - r1 C. r= r1 + r2 D. r= r1 * r2 E. r= r1 x r2

B. r= r2 - r1 r1 + r = r2 solve for r r= r2 - r1

Which of the motion diagrams in the figure below best matches the motion of the bungee jumper shown in the video?

C

A boat moves at 10.0 m/s relative to the water. If the boat is in a river where the current is 2.00 m/s, how long does it takes the boat to complete a round trip of 1000 m up stream and 1000 m down stream? A. 214 s B. 203 s C. 208 s D. 200 sterm-89 E. 194 s

C. 208 s

Suppose that C→=A→−B→. Under what circumstances is the length of C→ equal to the sum of the lengths of A→ and B→? A. Never B. Always. C. When A→ and B→ point in opposite directions. D. When A→ and B→ are parallel.

C. When A→ and B→ point in opposite directions.

Is the vertical component of velocity ever zero? If so, where? A. Yes, it is zero at points A and E. B. Yes, it is zero at all points. C. Yes, it is zero at point C. D. No, it is never zero.

C. Yes, it is zero at point C.

The SI base unit for mass is the _______. A. gram B. slug C. kilogram D. newton E. pound

C. kilogram

Which figure could represent the velocity versus time graph of a motorcycle whose speed is increasing?

D.

A baseball is thrown straight up at a speed of 30.0 m/s. What is the speed of the ball at 4.00 sec? A. 10.4 m/s B. 33.9 m/s C. -30.0 m/s D. -9.2 m/s E. 69.2 m/s

D. -9.2 m/s v = 30 - 9.8(4) = -9.2

In the calculation of the area of a rectangle with dimensions of 4.282 m by 0.050 m, which of the following answers has the correct number of significant figures? A. 0.2141 m^2 B. 0.214 m^2 C. 0.2 m^2 D. 0.21 m^2

D. 0.21 m^2

A helicopter is traveling at a constant speed of 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? A. 80 m/s B. 70 m/s C. 40 m/s D. 60 m/s E. 50 m/s

D. 60 m/s √9.8 x 4.51^2 x 40^2 =59.6

How does the magnitude of the horizontal velocity change as the human cannonball passes through points A, B, C, D, and E? A. It decreases. B. It increases. C. It decreases then increases. D. It does not change.

D. It does not change.

Suppose a runner completes one lap around a 400-m track in a time of 50 s. Calculate the magnitude of the average velocity of the runner.

0 m/s

Consulting the graph shown in (Figure 1), determine the object's average velocity over the time interval from 2 to 4 seconds.

5 m/s

Suppose a runner completes one lap around a 400-m track in a time of 50 s. Calculate the average speed of the runner.

8 m/s

Suppose you are hiking along a trail. Make a comparison between the magnitude of your displacement and your distance traveled. A. The magnitude of your displacement can be equal to your distance traveled. B. The magnitude of your displacement must be greater than your distance traveled. C. The magnitude of your displacement can be less than your distance traveled. D. The magnitude of your displacement must be equal to your distance traveled. E. The magnitude of your displacement must be less than your distance traveled.

A and C

The motorcycle engine on a Kawasaki Ninja 1000 has a displacement of 1043 cubic-centimeters (cm3). In order to calculate its engine displacement in cubic-inches (in3) what unit conversion factor would you use to multiply the given displacement? A. 1 in^3 / 16.4 cm^3 B. 2.54 cm^3 / 1 in^3 C. 6.45 cm^3 / 1 in^3 D. 1 in^3 / 2.54 cm^3

A. 1 in^3 / 16.4 cm^3

A sample of some material has a mass of 𝑚 = 256.0 g and a volume of 𝑉 = 112 cm3. What is the density of the sample, taking into account significant figures? A. 2.29 g/cm³ B. 2.2857 g/cm³ C. 2.286 g/cm³ D. 2.3 g/cm³ E. 2.28571 g/cm³

A. 2.29 g/cm³ Density = m/v 256/112 = 2.285714 g/cm^3 3 sig figs = 2.29 g/cm^3

An airplane travels at a speed of 300 m/s due East relative to the air. The wind is blowing due North at a speed of 50.0 m/s relative to the ground. What is the speed of the airplane relative to the ground? A. 304 m/s B. 300 m/s C. 250 m/s D. 350 m/s E. 296 m/s

A. 304 m/s

Starting from your campsite you walk 3.0 km east, 6.0 km north, 1.0 km east, and then 4.0 km west. How far are you from your campsite? A. 6.0 km B. 4.0 km C. 10.0 km D. 14.0 km

A. 6.0 km

A football player kicks a football in a field goal attempt. When the football reaches its maximum height, what is the relationship between the direction of the velocity and acceleration vectors? Assume air resistance is negligible. A. At the maximum height, the velocity and acceleration vectors are perpendicular to each other B. At the maximum height, the velocity and acceleration vectors are parallel to each other. C. At the maximum height, both the velocity and acceleration vectors are zero. D. At the maximum height, the velocity and acceleration vectors point in opposite directions.

A. At the maximum height, the velocity and acceleration vectors are perpendicular to each other

Which of the following best describes how to calculate the average acceleration of any object? A. Average acceleration is always equal to the change in velocity of an object divided by the time interval. B. Average acceleration is always equal to the change in speed of an object divided by the time interval. C. Average acceleration is always halfway between the initial acceleration of an object and its final acceleration. D. Average acceleration is always equal to the displacement of an object divided by the time interval.

A. Average acceleration is always equal to the change in velocity of an object divided by the time interval.

Vector A→ has a magnitude of 3.00 and is directed parallel to the negative y-axis and vector B→ has a magnitude of 3.00 and is directed parallel to the positive y-axis. Determine the magnitude and direction angle (as measured counterclockwise from the positive x-axis) of vector C→, if C→=A→ − B→. A. C = 6.00; θ = 270˚ B. C = 3.00; θ = 270˚ C. C = 6.00; θ = 90˚ D. C = 3.00; θ = 90˚ E. C = 0.00 (its direction is undefined)

A. C = 6.00; θ = 270˚

Which of the following is a vector? A. Displacement B. Distance C. Temperature D. Mass E. Speed

A. Displacement

A car has a velocity towards the north and simultaneously has an acceleration towards the south. What does this mean? A. The car is slowing down. B. The driver is intoxicated. C. The car is speeding up. D. Nonsense! This cannot happen. E. The car is turning.

A. The car is slowing down.

Which of the following is the basis of the current standard for the meter? A. The meter is defined as the distance that light travels in a specified time interval. B. The meter is defined as a specified number of wavelengths of the orange-red light emitted by krypton-86. C. The meter is defined as the length of a strand of carbon fiber that consists of a specified number of carbon-12 atoms. D. The meter is defined as the distance between precise scratch marks on a certain platinum-iridium bar that is kept under specified conditions. E. The meter is defined in terms of the standard inch so that 2.54 cm is exactly 1 inch.

A. The meter is defined as the distance that light travels in a specified time interval.

A swimmer is determined to cross a river that flows due south with a strong current. Initially, the swimmer is on the west bank desiring to reach a camp directly across the river on the opposite bank. In which direction should the swimmer head? A. The swimmer should swim northeast. B. The swimmer should swim southeast. C. The swimmer should swim due north. D. The swimmer should swim south. E. The swimmer should swim due east.

A. The swimmer should swim northeast.

A red toy car has an acceleration of 4.00 m/s², whereas a blue toy car has an acceleration of 2.00 m/s². You start the blue car from rest down a track of length 9.00 m. How much time must you wait before starting the red car from rest, such that the two cars reach the end of the track at the same time? A. 5.12 s B. 0.879 s C. 4.18 s D. 3.00 s E. 1.41 s

B. 0.879 s S = ut + 1/2at^2 9 = (0)(tr) + 1/2 (4)(tr)^2 9 = 2(tr)^2 tr = √9/2 tr = 2.12 secs 9 = (0)(tr) + 1/2 (2)(tb)^2 9 = tb^2 tb = √9 tb = 3 seconds 3-2.12 = = 0.879 s

A leaky faucet drips once each second. At this rate, it takes 1 hour to fill a 1-liter graduated cylinder to the 200-cm3 mark. What unit conversion do you need in order to calculate the average volume of a single drop in cm3? A. 1 hour equals 60 minutes B. 1 hour equals 3600 seconds C. 1 m^3 equals 10^3 liters D. 1 liter equals 10^3 cm^3

B. 1 hour equals 3600 seconds

A square solar collector measures 6.00 m by 6.00 m and another square solar collector measures 8.000 m by 8.000 m. Using the correct number of significant figures, what is the combined area of both collectors? A. 1.00 × 10^2 m^2 B. 1.000 × 10^2 m^2 C. 1.0000 × 10^2 m^2 D. 1.0 × 10^2 m^2 E. 1 × 10^2 m^2

B. 1.000 × 10^2 m^2

The position of a wind-up toy is given by: x(t)=t^2(1+7t−12t^2+5t^3) over the domain of {0 s < 𝑡 < 1 s}, where 𝑥 is in m, and 𝑡 is in s. What is the maximum speed of the toy? A. 0.139 m/s B. 1.82 m/s C. 0.0433 m/s D. 0.454 m/s E. 5.53 m/s

B. 1.82 m/s take derivative v = 2t + 21t^2 - 48t^3 + 25t^4 take derivative again 2 + 42t - 144t^2 + 100t^3 = 0 t = -0.4815, 1 , 0.4815 only 0.4815 fits in the domain vmax = 2x(.4815)^3 + 21(.4815)^2 -48(0.4815)^3 + 25(.4815)^4 Vmax = 1.8171 m/sec

The position of a child on a merry-go-round is given by: where R = 3.2 m and omega = 5.1 rad/s. What is the speed of the child when the position vector points in the negative j-hat direction? A. 8.1 m/s B. 16.3 m/s C. 83.2 m/s D. 27.1 m/s E. 3.2 m/s

B. 16.3 m/s

A helicopter is traveling at a constant speed of 40 m/s at a constant altitude of 100 m over a level field. If a wheel falls off the helicopter, what is the horizontal distance the wheel travels before hitting the ground? A. 45m B. 180m C. 18m D. 290m E. 87m

B. 180m 40 x 4.51 (from last question)

Consider the vectors: Calculate the dot product. A. 19 B. 30 C. √139 D. √14 E. 10

B. 30 (2, 1, 3) * (5, 2, 6) = (10,2,18) 10 + 2 + 18 = 30

Consider the vectors: Calculate the cross product. A. 3j^ + k^ B. 3j^ - k^ C. -3j^ - k^ D. -3j^ + k^ E. 7i^ + 3j^ + 9k^

B. 3j^ - k^ (6)(1) - (3)(2) = 0 (5)(3) - (6)(2) = 3 (2)(2) - (5)(1) = -1 3j^ - 1k^

On the Moon, where air resistance is negligible, an astronaut drops a rock from a cliff and notes that the rock has a speed v after falling from its point of release for a time t. Assuming that the rock does not hit the ground first, how fast will it be moving after it has fallen for a time 4t from its point of release? A. 16v B. 4v C. 2v D. 8v

B. 4v

Vector A→, which is shown in the figure, has a magnitude of 10 and a direction angle of 60º. What is the magnitude and direction angle (as measured counterclockwise from the positive x-axis) of −A→/2? A. 5, -30º B. 5, 240º C. -5, -30º D. -5, 240º E. -5, 60º

B. 5, 240º

A baseball is thrown straight up at a speed of 30.0 m/s. How much time will elapse for the ball to return to the ground? A. 1.53 s B. 6.12 s C. 12.2 s D. 3.06 s E. 9.18 s

B. 6.12 s t = 2v0/g 2(30)/9.80 = 6.12 s OR 30t - 1/2 (9.8) t^2 t = 6.12

Which of the following equations correctly expresses the relation between vectors A→,B→, and C→ shown in the figure? A. C→ = A→ + B→ B. B→ = A→ + C→ C. A → + B → + C → = 0 D. A→ = B→ + C→

B. B→ = A→ + C→

The meter was originally based on what standard? A. Some fraction of the distance to the Moon. B. Some aspect of the size of the human body. C. None of these. D. Some fraction of the height of the Louvre museum.

B. Some aspect of the size of the human body.

Suppose a car's velocity is to the left, and its acceleration is to the right. Which of the following describes this car's motion? A. The car is speeding up B. The car is slowing down. C. The car is moving at a constant speed.

B. The car is slowing down.

A car traveling due east at 20 m/s reverses its direction over a period of 10 seconds so that it is now traveling due west at 20 m/s. What is the direction of the car's average acceleration over this period? A. The car's average acceleration is zero. B. The car's average acceleration points due west. C. The car's average acceleration points due east. D. The direction of the car's average acceleration cannot be determined from the given information.

B. The car's average acceleration points due west.

For a projectile launched horizontally, which of the following best describes the horizontal component of a projectile's velocity? Assume air resistance is negligible. A. The horizontal component of the projectile's velocity is zero. B. The horizontal component of the projectile's velocity remains a nonzero constant. C. The horizontal component of the projectile's velocity continually increases. D. The horizontal component of the projectile's velocity continually decreases. E. The horizontal component of the projectile's velocity initially decreases and then increases.

B. The horizontal component of the projectile's velocity remains a nonzero constant.

A player kicks a soccer ball in a high arc toward the opponent's goal. When the soccer ball reaches its maximum height, how does its speed at this point compare to its initial speed? Assume air resistance is negligible. A. The speed at its highest point cannot be determined unless the angle at which the soccer ball is kicked is known. B. The speed at its highest point is less than its initial speed. C. The speed at its highest point is greater than its initial speed. D. The speed at its highest point is equal to its initial speed. E. The speed at its highest point is zero.

B. The speed at its highest point is less than its initial speed.

On a straight road, a car speeds up at a constant rate from rest to 20 m/s over a 5 second interval and a truck slows at a constant rate from 20 m/s to a complete stop over a 10 second interval. How does the distance traveled by the truck compare to that of the car? A. The truck travels half as far as the car. B. The truck travels twice as far as the car. C. The truck travels the same distance as the car. D. There is not enough information to answer the question.

B. The truck travels twice as far as the car.

In the equation z = ct + d, z is measured in meters and t is measured in seconds. What are the dimensions (units) of d? A. m*s B. m C. s D. s/m E. m/s

B. m

The position of an object is given by: x(t)=X exp(−t/T) where 𝑋 and 𝑇 are constants. The velocity is thus:

B. v(t) = -X/T exp (-t/T)

The acceleration of an object is given by: a(t)=A cos⁡(ωt) where A and ω are constants. The velocity is given by:

B. v(t) = v0 + A/ω sin(ωt)

A red toy car has an acceleration of 4.00 m/s², whereas a blue toy car has an acceleration of 2.00 m/s². You start the blue car from rest down a track of length 9.00 m. What is the position of the blue car before starting the red car from rest, such that the two cars reach the end of the track at the same time? A. 8.10 m B. 4.87 m C. 0.772 m D. 6.08 m E. 2.67 m

C. 0.772 m 1/2 (-1 + √2)^2 L 0.7720 WHAT

How many millimeters are there in one meter? A. 10^6 B. 10^-6 C. 10^3 D. 10^-3

C. 10^3

On Mars, where air resistance is negligible, an astronaut drops a rock from a cliff and notes that the rock falls about d meters during the first t seconds of its fall. Assuming the rock does not hit the ground first, how far will it fall during the first 4t seconds of its fall? A. 2d B. 8d C. 16d D. 4d

C. 16d

Force F1 is 3.0 N and points along the positive x-axis; force F2 is 4.0 N and points along a direction 150° from the positive x-axis. What is the magnitude of the resultant net force? A. 4.7 N B. 7.0 N C. 2.1 N D. 1.0 N E. 6.1 N

C. 2.1 N i=x. j=y A= (cos0*3i) +(sin0*0j) A= 3i + 0j B= (cos30 *4i) +(4*sin30) B= -3.46i +2j R=A+B R= (3i+0j)+(-3.46i+2j) = -.46i + 2j R^2= A^2 +B^2 plug into =2.1

A microbe is about 1 μm in diameter, and a typical Petri dish is 50 mm in diameter. Estimate the number of microbes needed to fill a Petri dish. A. 4.0 x 10^10 B. 3.3 x 10^6 C. 2.5 x 10^9 D. 2.5 x 10^3 E. 5.0 x 10^4

C. 2.5 x 10^9 (50 * 10^-3)/(1.0 * 10^-6)

Convert the speed of 65 mi/hr into metric units. A. 38 m/s B. 230 m/s C. 29 m/s D. 112 m/s E. 14 m/s

C. 29 m/s 1 mile = 1609.344 meters 1 hour = 3600 seconds 65 mi/hr (1 hr/ 3600 seconds) (1609.344 meters/ 1 mi) = 29.0576

The sum of the x components of vectors A and B in (Figure 1) is ___. A. 6 B. 14 C. 4 D. -5

C. 4

A baseball is thrown straight up at a speed of 30.0 m/s. At what time will the ball be at a height of 25.0 m? A. 3.44 s B. 0.743 s C. 5.13 s D. 6.87 s E. 0.995 s

C. 5.13 s E. 0.995 s 25 = 30t - 1/2 (9.8) t^2 = 5.13 , 0.995

Momentum is given by the formula above. If the velocity is 20 m/s at an angle of 60° from the positive x-axis, and the mass is 50 kg, what is the x-component of the momentum? A. 1000 kg·m/s B. 2250 kg·m/s C. 500 kg·m/s D. 866 kg·m/s E. 1220 kg·m/s

C. 500 kg·m/s px = mv(cos 60) (50)(20)(cos 60) =500

Vector A→ has a magnitude of 2.00 m and vector B→ has a magnitude of 5.00 m. If the direction of each vector is unknown, what is the largest possible value for the magnitude of A→−B→? A. 3.00 m B. 5.39 m C. 7.00 m D. -3.00 m

C. 7.00 m

The position of a child on a merry-go-round is given by: where R = 3.2 m and omega = 5.1 rad/s. What is the magnitude of the acceleration of the child when the acceleration vector is anti-parallel to the position vector? A. 8.1 m/s^2 B. 3.2 m/s^2 C. 83.2 m/s^2 D. 27.1 m/s^2 E. 16.3 m/s^2

C. 83.2 m/s^2

In the study of physics, what distinguishes a scalar from a vector? A. A scalar must always be positive, but vectors can be positive, negative, or zero. B. A scalar is a dimensionless number, while vectors are numbers that have dimensions. C. A scalar is specified with a single number, but a vector is specified using both a magnitude and a direction. D. Scalars have both a magnitude and a direction, but vectors have only a magnitude. E. Nothing—the terms "vector" and "scalar" are different names for the same thing.

C. A scalar is specified with a single number, but a vector is specified using both a magnitude and a direction.

Which of the following equations correctly expresses the relation between vectors A→, B→, C→, and D→ shown in the figure? A. A→ + B→ + C→ + D→ = 0 B. A→ + B→ - C→ + D→ = 0 C. A→ + B→ - C→ - D→ = 0 D.A→ - B→ - C→ + D→ = 0

C. A→ + B→ - C→ - D→ = 0

How does the vertical acceleration at point A compare to the vertical acceleration at point C? A. The acceleration at A is greater than that at C. B. The acceleration at A is less than that at C. C. Both accelerations are equal to free fall acceleration. D. Both accelerations are equal to zero.

C. Both accelerations are equal to free fall acceleration.

For general projectile motion, which of the following best describes the horizontal component of a projectile's acceleration? Assume air resistance is negligible. A. The horizontal component of a projectile's acceleration remains a nonzero constant. B. The horizontal component of a projectile's acceleration continually increases. C. The horizontal component of a projectile's acceleration is zero. D. The horizontal component of a projectile's acceleration continually decreases. E. The horizontal component of a projectile's acceleration initially decreases and then increases.

C. The horizontal component of a projectile's acceleration is zero.

A pilot releases a package from a plane flying horizontally at a constant speed. When the package reaches the ground below, what is the horizontal location of the plane with respect to the package? Assume air resistance is negligible. A. The plane will be located behind the package. B. The location of the plane with respect to the package will depend on the initial height of the plane when the package was released. C. The plane will be located directly above the package. D. The plane will be located ahead of the package.

C. The plane will be located directly above the package.

An object moves in a circular path at a constant speed. What is the relationship between the directions of the object's velocity and acceleration vectors? A. The velocity and acceleration vectors point in opposite directions. B. The velocity vector points toward the center of the circular path. The acceleration is zero. C. The velocity and acceleration vectors are perpendicular. D. The velocity vector points in a direction tangent to the circular path. The acceleration is zero E. The velocity and acceleration vectors point in the same direction.

C. The velocity and acceleration vectors are perpendicular.

A helicopter is traveling at a constant speed of 40 m/s at a constant altitude of 100 m over a level field. If a wheel falls off the helicopter, how much time will it take for it to hit the ground? (Air resistance is negligible.) A. 3.2s B. 2.3s C. 5.5s D. 4.5s E. 0.44s

D. 4.5s 100 = 1/2 (9.8) t^2 = 4.5

A baseball is thrown straight up at a speed of 30.0 m/s. What is the height of the ball at 2.00 s? A. 25.1 m B. 34.0 m C. 34.9 m D. 40.4 m E. 79.6 m

D. 40.4 m x = 30(2) - 1/2 (9.8)(2.0)^2 x = 40.4

For a projectile launched horizontally, which of the following best describes the downward component of a projectile's velocity? Assume air resistance is negligible. A. The downward component of the projectile's velocity continually decreases. B. The downward component of the projectile's velocity initially decreases and then increases. C. The downward component of the projectile's velocity remains a nonzero constant. D. The downward component of the projectile's velocity continually increases. E. The downward component of the projectile's velocity is zero.

D. The downward component of the projectile's velocity continually increases.

A red water balloon is thrown horizontally from the top of a bridge. At the same instant, a yellow water balloon is dropped off the bridge from the same height. Compare the time of fall for the two balloons. Assume air resistance is negligible. A. The yellow balloon hits the ground first. B. The time of fall depends on the amount of water placed in each of the balloons. C. The red water balloon hits the ground first. D. The two balloons hit the ground at the same time.

D. The two balloons hit the ground at the same time.

During free-fall, the acceleration of a bungee jumper ____________. A. decreases in magnitude B. increases in magnitude C. is zero D. is a nonzero constant

D. is a nonzero constant

What is the average acceleration of a car that maintains a constant velocity of 100 km/hr for 10 seconds? A. 10 km/hr·s B. 0.1 km/hr·s C. 1000 km/hr·s D. 0.001 km/hr·s E. 0 km/hr·s

E. 0 km/hr·s avgVelocity / avgTime = avgAcceleration 100 - 100 / 10

A car rounds a turn at a constant centripetal acceleration of 9.0 m/s² while slowing with a tangential acceleration of 12 m/s². What is the car's total acceleration? A. 10 m/s² B. 14 m/s² C. 12 m/s² D. 9.0 m/s² E. 15 m/s²

E. 15 m/s²

The average speed of a horse that gallops a distance of 10 mi in a time of 30 minutes is: A. 300 mph B. 0.333 mph C. 10 mph D. 30 mph E. 20 mph

E. 20 mph Avg = total distance/ total time 10/.5(hours) = 20 mph

The radius of the earth is 6,380 kilometers. What is the radius of the earth in centimeters? A. 6.38 × 10^5 cm B. 6.38 × 10^4 cm C. 6.38 × 10^2 cm D. 6.38 × 10^-2 cm E. 6.38 × 10^8 cm

E. 6.38 × 10^8 cm

A car rounds a turn at a constant speed of 30 m/s with a radius of 100 m. What is the car's centripetal acceleration? A. 0 m/s^2 B. 330 m/s^2 C. 0.3 m/s^2 D. 3000 m/s^2 E. 9.0 m/s^2

E. 9.0 m/s^2 (30)^2 / 100 =9

The kilogram was originally based on what standard? A. The mass of 10 shillings. B. The average mass of four apples. C. The mass of 1000 cm³ of seawater. D. The average mass of a human heart. E. None of these.

E. None of these.

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? A. The acceleration of the car is positive and increasing. B. The acceleration of the car is negative and decreasing. C. The acceleration of the car is negative and increasing. D. The acceleration of the car is constant. E. The acceleration of the car is positive and decreasing.

E. The acceleration of the car is positive and decreasing.

For general projectile motion, which of the following best describes the horizontal component of a projectile's velocity? Assume air resistance is negligible. A. The horizontal component of a projectile's velocity is zero. B. The horizontal component of a projectile's velocity continually decreases. C. The horizontal component of a projectile's velocity continually increases. D. The horizontal component of a projectile's velocity initially decreases and then increases. E. The horizontal component of a projectile's velocity remains a nonzero constant.

E. The horizontal component of a projectile's velocity remains a nonzero constant.

Suppose that you toss a rock upward so that it rises and then falls back to the earth. If the acceleration due to gravity is 9.8 m/sec2, what is the rock's acceleration at the instant that it reaches the top of its trajectory (where its velocity is momentarily zero)? Assume that air resistance is negligible. A. The rock has an upward acceleration of 19.6 m/s^2. B. The acceleration of the rock is zero. C. The rock has a downward acceleration of 19.6 m/s^2. D. The rock has an upward acceleration of 9.8 m/s^2. E. The rock has a downward acceleration of 9.8 m/s^2.

E. The rock has a downward acceleration of 9.8 m/s^2.

Which of the following is a vector quantity? A. temperature B. velocity C. acceleration D. speed E. displacement F. mass G. time H. force

Velocity, acceleration, displacement, force

Which of the following equations correctly expresses the relation between vectors A→, B→, and C→ shown in the figure? A. C→ = A→ + B→ B. A → + B → + C → = 0 C. A→ = B→ + C→ D. B→ = A→ + C→

A → + B → + C → = 0

The paths of flight for three cannonballs are shown. If all three are fired at the same time, and all three reach the same maximum height, which reaches the ground first? A. All reach the ground at the same time B. Path C C. Path A D. Path B

A. All reach the ground at the same time

At what angle, above the horizon, should a cannon be fired in order for the cannon ball to obtain the greatest horizontal range? Assume air resistance is negligible. A. The cannon should be fired at an angle of 45° above the horizon. B. The cannon should be fired vertically, at an angle of 90° above the horizon. C. The cannon should be fired at an angle of 60° above the horizon. D. The cannon should be fired at an angle of 30° above the horizon.

A. The cannon should be fired at an angle of 45° above the horizon. R = (v0^2 sin 2theta) / g 2theta = sin^-1 (1) 90/2 = 45

What shape do we expect for a graph showing the position of a motorcycle versus time if the motorcycle is speeding up with a constant acceleration? A. The position versus time graph is parabolic. B. The position versus time graph is a line with a negative slope. C. The position versus time graph is a horizontal line. D. The position versus time graph is a line with a positive slope.

A. The position versus time graph is parabolic.

The second was originally based on what standard? A. The rotation of the Earth. B. None of these. C. The orbit of the Earth around the Sun. D. The time it takes an object to fall one meter. E. The orbit of the Moon around the Earth.

A. The rotation of the Earth.

The kinetic energy for a moving object is given by KE=1/2mv^2. Which of the following gives the correct units for energy? A. kg·m²/s² B. kg·m/s² C. kg·m²/s D. kg·m/s E. kg²·m²/s²

A. kg·m²/s² Mass is in kg, velocity squared is (m/s)^2

The sum of two vectors is the largest when the two vectors are _____. A. pointing in the same direction B. pointing in opposite directions C. perpendicular to each other D. positioned at a 45° angle

A. pointing in the same direction

The position of a body is given by: equation in previous question where 𝑅 and 𝛾 are constants. What is the velocity when the speed is at a minimum.

B