Physics Chapter 2&3

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 29.1 m/s at an initial angle of 30.0° with respect to the horizontal. What is the maximum vertical displacement that the ball reaches during its trajectory?​ A. 10.8 m B. 21.6 m C. 32.4 m D. 14.4 m E. 28.8 m

A.

A projectile is launched at an angle θ above the horizontal. Three seconds later the projectile is moving the same angle θ below the horizontal. Which of the following (actual values with units, not just algebraic symbols) can be found from the information given? A. the initial vertical component of the projectile's velocity B. the initial horizontal component of the projectile's velocity C. the initial magnitude of the velocity D.None of the above since at least one of the above must be given to find the other two values.

A.

A basketball player can jump 1.6 m off the hardwood floor. With what upward velocity did he leave the floor?​ A. 5.8 m/s B. 2.8 m/s C. 5.4 m/s D. 5.6 m/s ​E. 11 m/s

D.

A Cessna aircraft has a lift-off speed of 135 km/h. What minimum constant acceleration does this require if the aircraft is to be airborne after a take-off run of 260 m?​ A. 2.70 m/s2 B. 1.35 m/s2 C. 3.38 m/s2 D. 5.41 m/s2 E. 2.03 m/s2

A.

A car's initial velocity is 50.0 km/h in the direction 60.0° north of east, and its final velocity is 70.0 km/h in the direction 40.0° south of east. If the time period for this journey is 30.0 minutes, what is the magnitude of the car's average acceleration? A. 186 km/h/h B. 240 km/h/h C. 92.8 km/h/h D. 3.94 km/h/h

A.

A plane is moving due north, directly towards its destination. Its airspeed is 210 mph. A constant breeze is blowing from west to east at 20.0 mph. At what rate is the plane moving north? A. 209 mph B. 211 mph C. 204 mph D. 199 mph E. 194 mph

A.

A rock is thrown straight up with an initial velocity of 17.6 m/s. What time interval elapses between the rock's being thrown and its return to the original launch point? (Acceleration due to gravity is 9.80 m/s2.) A. 3.60 s B. 1.80 s C. 2.70 s D. 3.06 s E. 3.96 s

A.

Amanda is standing at the edge of a cliff. She throws a rock vertically upward at speed v0, while at the same time throws a second rock vertically downward at the same speed. How long after the rock thrown downward hits the ground does the rock thrown upwards hit? A. 2v0/g B. v0/g

A.

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? A. It is positive. B. It is negative. C. It is zero. D. It can be positive, negative, or zero.

A.

Which of the following is not a vector quantity? A. temperature B. velocity C. acceleration D. displacement

A.

Wiley Coyote has missed the elusive road runner once again. This time, he leaves the edge of the cliff at 52.4 m/s horizontal velocity. If the canyon is 140 m deep, how far from his starting point at the edge of the cliff does the coyote land? A. 280 m B. 198 m C. 396 m D. 140 m E. 70.0 m

A.

A bird, accelerating from rest at a constant rate, experiences a displacement of 25 m in 12 s. What is its acceleration? A. 0.18 m/s2 B. 0.35 m/s2 C. 0.44 m/s2 D. 0.26 m/s2 E. 0.53 m/s2

B.

A bridge that was 10.4 m long has been washed out by the rain several days ago. How fast must a car be going to successfully jump the stream, if we neglect air resistance? Although the road is level on both sides of the bridge, the road on the far side is 3.00 m lower than the road on this side. A. 18.8 m/s B. 13.3 m/s C. 10.9 m/s D. 26.6 m/s E. 14.3 m/s

B.

A car is moving along a straight highway and accelerates at a constant rate while going from point A to point B. If the acceleration is positive, increasing the speed of the car, where does the position where the instantaneous speed equals the average speed occur for the interval from A to B? A. midway between A and B B. closer to A than to B C. closer to B than to A D. Any of the answers could be correct depending on the original speed.

B.

A cheetah can maintain its maximum speed of 96.0 km/hr for 26.0 seconds. What minimum distance must a gazelle running 85.0 km/hr be ahead of the cheetah to escape? A. 96 m B. 79 m C. 40 m D. 73 m E. ​67 m

B.

A rock is thrown straight down with an initial velocity of 14.3 m/s from a cliff. What is the rock's displacement after 2.0 s? (Acceleration due to gravity is 9.80 m/s2.) A. 81 m B. 48 m C. 38 m D. 22 m E. 31 m

B.

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? A. 1st B. 2nd C. 3rd D. None, since the object is now moving in the y-direction.

B.

Consider the magnitude of the average speed, v​avg, speed, mag, and the magnitude of the average velocity, v​avg, velocity, mag, for the same trip. Which of the following is always true? A. v​avg, speed, mag = v​avg, velocity, mag​ B. v​avg, speed, mag ≥ v​avg, velocity, mag C. v​avg, speed, mag ≤ v​avg, velocity, mag​ D. none of the above

B.

In a two-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? A. sine B. cosine C. tangent D. cotangent

B.

Suppose a particle is moving along a straight line with a speed v for a time t, then stops for a time t, and then resumes moving along the original direction with speed v for time t. What has been the average speed of the particle for the total time period 3t? A. v B. 2v/3 C. 1.5v D. Square root of 2/3v

B.

A European sports car dealer claims that his product will accelerate at a constant rate from rest to a speed of 100 km/h in 6.00 s. What distance will the sports car travel during the 6.00-s acceleration period? (Hint: First convert speed to m/s.) A. 41.7 m B. 58.3 m C. 83.3 m D. 167 m E. 125 m

C.

A boat moves at 10.8 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 take the boat to make a complete round trip of 1 100 m upstream followed by a 1 100-m trip downstream? A. 250 s B. 172 s C. 211 s D. 297 s E. ​336 s

C.

A fireman, 57.6 m away from a burning building, directs a stream of water from a fire hose at an angle of 35.2° above the horizontal. If the initial speed of the stream is 42.7 m/s, at what height will the stream of water strike the building?​ A. 44.2 m B. 13.8 m C. 27.3 m D. 30.8 m E. 36.4 m

C.

A projectile is launched with speed v at an angle θ, the angle being less than 45º. What other angle would give the same range for this projectile launched at the same speed v? A. 2θ B. 0.5θ C. 90° - θ D. 90º - 0.5θ

C.

An object moves at a constant velocity of 12 m/s to the southwest for an interval of 20 s. Halfway through this interval, what is the magnitude of its instantaneous velocity? A. It can be any value from 0 to 24 m/s. B. 6 m/s C. 12 m/s D. More information is needed.

C.

In the case of constant acceleration, the average velocity equals the instantaneous velocity: A. at the beginning of the time interval. B. at the end of the time interval. C. half-way through the time interval. D. three-fourths of the way through the time interval.

C.

Omar throws a rock down with speed 12.5 m/s from the top of a tower. The rock hits the ground after 1.50 s. What is the height of the tower? (air resistance is negligible)​ A. 24.0 m B. 21.0 m C. 30.0 m D. 54.0 m ​E. 45.0 m

C.

A ball is launched from ground level at 25 m/s at an angle of 31° above the horizontal. How far does it go before it is at ground level again? A. 34 m B. 94 m C. 28 m D. 56 m E. 14 m

D.

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? (air resistance is negligible) A. just after leaving the center fielder's hand B. just before arriving at the catcher's mitt C. at the top of the trajectory D. acceleration is constant during entire trajectory

D.

A rifle is aimed horizontally toward the center of a target 120 m away. If the bullet strikes 11.2 cm below the center, what was the velocity of the bullet? (Ignore air friction.) A. 23 m/s B. 1 120 m/s C. 32 m/s D. 790 m/s E. 400 m/s

D.

An object is dropped from a height. Once it is moving, which of the following statements is true, at least at one point? A. Its velocity is more than its acceleration. B. Its velocity is less than its acceleration. C. Its velocity is the same as its acceleration. D. Its velocity is never equal to its acceleration.

D.

Which formula is dimensionally consistent with an expression yielding a value for velocity? (a is acceleration, x is distance, and t is time) A. v/t2 B. vx2 C. v2/t D. at

D.

Human reaction time is usually about 0.18 s. If your lab partner holds a ruler between your finger and thumb and releases it without warning, how far can you expect the ruler to fall before you catch it? The nearest value is​ A. 32 cm. B. 88 cm. C. 1.6 cm. D. 180 cm. ​E. 16 cm.

E.

A rock is rolled in the sand. It starts at 5.0 m/s, moves in a straight line for a distance of 6.0 m, and then stops. What is the magnitude of the average acceleration? A. 2.1 m/s2 B. 4.2 m/s2 C. 5.4 m/s2 D. 6.2 m/s2

A.

An object moves 10.0 m east in 10.0 s and then returns to its starting point taking an additional 40.0 s. If west is chosen as the positive direction, what is the average speed of the object? A. 0.4 m/s B. -0.4 m/s C. 10.0 m/s D. 0 m/s ​E. -10.0

A.

Gwen releases a rock at rest from the top of a 40-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the speed of the rock as it hits the ground?​ A. 28 m/s B. 14 m/s C. 20 m/s D. 40 m/s ​E. 780 m/s

A.

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 A. positive, positive. B. positive, negative. C. negative, negative. D. negative, positive.

A.

Mt. Everest is more than 8 000 m high. How fast would an object be moving if it could free fall to sea level after being released from an 8 000-m elevation? (Ignore air resistance.) A. 396 m/s B. 120 m/s C. 1 200 m/s D. 12 000 m/s

A.

In a two-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? A. sine B. cosine C. tangent D. cotangent

B.

The distance of the Earth from the Sun is 93 000 000 miles. If there are 3.15 × 107 s in one year, find the speed of the Earth in its orbit about the Sun. A. 9.28 miles/s B. 18.6 miles/s C. 27.9 miles/s D. 37.2 miles/s

B.

A truck moves 80.0 m east, then moves 140.0 m west, and finally moves east again a distance of 80.0 m. If east is chosen as the positive direction, what is the truck's resultant displacement? A. 20.0 m B. -20.0 m C. 300.0 m D. -300.0 m ​E. 140.0 m

A.

A track star in the broad jump goes into the jump at 12.0 m/s and launches himself at 26.0° above the horizontal. How long is he in the air before returning to Earth? (g = 9.8 m/s2) A. 0.5 s B. 1.1 s C. 2.1 s D. 2.2 s E. 1.2 s

B.

A v vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the acceleration of the ball is zero. We know that at t = 5 s, A. the slope of the curve is non-zero. B. the velocity of the ball is not changing. C. the curve is not crossing the time axis. D. the curve is at v = 0, t = 0.

B.

A bird, accelerating from rest at a constant rate, experiences a displacement of 25 m in 15 s. What is the final velocity after 15 s?​ A. 2.5 m/s B. 1.7 m/s C. 3.3 m/s D. 3.8 m/s ​E. Zero

C.

A helicopter is traveling at 50.0 m/s at a constant altitude of 150 m over a level field. If a wheel falls off the helicopter, with what speed will it hit the ground? (g = 9.8 m/s2 and air resistance negligible)​ A. 63 m/s B. 55 m/s C. 74 m/s ​D. 54 m/s

C.

A water rocket, launched from the ground, rises vertically with acceleration of 25 m/s2 for 2.0 s when it runs out of "fuel." Disregarding air resistance, how high will the rocket rise? A. 305 m B. 356 m C. 178 m D. 130 m ​E. 50 m

C.

On a position-time graph for a particle, suppose the plot starts at some positive position and as the time goes on the curve gets steeper and steeper while curving upwards. Which of the following must be true? A. The speed of the particle is constant. B. The acceleration of the particle is constant. C. The speed of the particle is decreasing. D. The acceleration of the particle is positive.

D.

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stop watch measures the ball's trajectory time from table to the floor to be 0.20 s. How far away from the table does the ball land? (g = 9.8 m/s2 and air resistance is negligible) A. 0.24 m B. 0.048 m C. 0.39 m D. 0.15 m E. 0.47 m

B

Maria throws two stones from the top edge of a building with a speed of 22 m/s. She throws one straight down and the other straight up. The first one hits the street in a time t1. How much later is it before the second stone hits? A. 5.5 s B. 4.5 s C. 3.5 s D. 6.5 s

B.

A baseball player throws a ball straight up into the air. At a height of 3.00 m above the release point, the ball is moving at 1.25 m/s. What was the ball's initial speed? A. 7.56 m/s B. 7.77 m/s C. 57.2 m/s D. 60.4 m/s

B.

The slope of the acceleration vs. time curve represents A. the velocity. B. the rate of change of acceleration. C. the rate of change of displacement. D. the area under the position vs. time curve

B.

A ball rolls down an incline, starting from rest. If the total time it takes to reach the end of the incline is T, how much time has elapsed when it is halfway down the incline? A. 0.5 T B. < 0.5 T C. > 0.5 T D. More information is needed.

C.

Plane A is flying at 440 mph in the northeast direction relative to the Earth. Plane B is flying at 550 mph in the north direction relative to the Earth. What is the speed of Plane B as observed from Plane A? A. 570 mph B. 916 mph C. 392 mph D. 704 mph E. 714 mph

C.

Superguy is flying at treetop level near Paris when he sees the Eiffel Tower elevator start to fall (the cable snapped). His x-ray vision tells him Lois LaTour is inside. If Superguy is 1.00 km away from the tower, and the elevator falls from a height of 230 m, how long does Superguy have to save Lois, and what must be his average speed?​ A. 4.84 s, 206 m/s B. 8.39 s, 119 m/s C. 6.85 s, 150 m/s D. 9.69 s, 103 m/s ​E. 3.43 s, 292 m/s

C.

A stone is thrown with an initial speed of 11.5 m/s at an angle of 50.0 above the horizontal from the top of a 30.0-m-tall building. Assume air resistance is negligible, and g = 9.8 m/s2. What is the magnitude of the horizontal-velocity component of the rock as it hits the ground? A. 79.5 m/s B. 8.81 m/s C. 58.7 m/s D.7.39 m/s

D.

A string attached to an airborne kite is maintained at an angle of 44.0° with the horizontal. If a total of 160 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.) A. 111 m B. 80.0 m C. 31.7 m D. 115 m E. 155 m

D.

When a drag strip vehicle reaches a velocity of 65.0 m/s, it begins a negative acceleration by releasing a drag chute and applying its brakes. While reducing its velocity back to zero, its acceleration along a straight-line path is a constant −7.10 m/s2. What displacement does it undergo during this deceleration period? A. 595 m B. 4.58 m C. 2 110 m D. 298 m ​E. 9.15 m

D.

A mouse starts out in a corner of a room, and runs across the floor according to the following displacements: d1: 1.2 m + 0.4 m d2: 0.2 m - 0.8 m What is the magnitude of the total displacement of the mouse's position? A. 1.5 m B. 2.6 m C. 1.0 m D. 1.8 m

A.

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? A. midway on the way up B. at the top of its trajectory C. the instant it leaves the catcher's hand D. the instant before it arrives in the catcher's mitt

B.

A baseball is released at rest from the top of the Washington Monument. It hits the ground after falling for 5.85 s. What was the height from which the ball was dropped? (g = 9.80 m/s2 and assume air resistance is negligible)​ A. 1.88 × 102 m B. 1.68 × 102 m C. 1.38 × 102 m D. 3.36 × 102 m

B.

A bird, accelerating from rest at a constant rate, experiences a displacement of 22 m in 10 s. What is the average velocity? A. 1.2 m/s B. 2.2 m/s C. 2.4 m/s D. 0 m/s E. ​0.5 m/s

B.

A ball of relatively low density is thrown upwards. Because of air resistance the acceleration while traveling upwards is −10.8 m/s2. On its trip downward the resistance is in the opposite direction, and the resulting acceleration is −8.8 m/s2. When the ball reaches the level from which it was thrown, how does its speed compare to that with which it was thrown? A. It is greater than the original speed upward. B. It is the same as the original speed upward. C. It is less than the original speed upward. D. Without knowing the original speed, this problem cannot be solved

C.

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) A. just after leaving the center fielder's hand B. just before arriving at the catcher's mitt C. at the top of the trajectory D. speed is constant during entire trajectory

C.

A baseball leaves the bat with a speed of 47 m/s and an angle of 45° above the horizontal. A 5.0-m-high fence is located at a horizontal distance of 137 m from the point where the ball is struck. Assuming the ball leaves the bat 1.0 m above ground level, by how much does the ball clear the fence? A. 59.7 m B. 47.7 m C. 49.7 m D. 121 m

C.

A speeding car traveling at a constant velocity of 24 m/s passes a police care initially at rest beside the roadway. If the police car with constant acceleration of 3.0 m/s2 immediately pursues the speeding car, how far down the road does it draw even with the speeding car? A. 190 m B. 290 m C. 380 m D. 770 m

C.

A ball is pushed with an initial velocity of 4.0 m/s. The ball rolls down a hill with a constant acceleration of 1.7 m/s2. The ball reaches the bottom of the hill in 7.0 s. What is the ball's velocity at the bottom of the hill? A. 15 m/s B. 13 m/s C. 14 m/s D. 16 m/s ​E. 19 m/s

D.

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stopwatch measures the ball's trajectory time from table to the floor to be 0.36 s. What is the height of the table? (g = 9.8 m/s2 and air resistance is negligible) A. 0.72 m B. 0.55 m C. 0.016 m D. 0.64 m E. 0.65 m

D.

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 28.3 m/s at an initial angle of 30.0° with respect to the horizontal. If it is in its trajectory for a total of 4.00 s before being caught by the third baseman at an equal shoulder-height level, what is the ball's net vertical displacement during its 4.00-s trajectory?​ A. 98.0 m B. 9.80 m C. 10.2 m D. zero ​E. 20.4 m

D.

In which of the following cases is the displacement's magnitude half the distance traveled?​ A. 10 steps east followed by 3 steps west B. 28 steps east followed by 14 steps west C. 6 steps east followed by 24 steps west D. 12 steps east followed by 4 steps west ​E. 5 steps east followed by 25 steps west

D.

The highest mountain on Mars is Olympus Mons, rising 22 000 meters above the Martian surface. If we were to throw an object horizontally off the mountain top, how long would it take to reach the surface? (Ignore atmospheric drag forces and use gMars = 3.72 m/s2.) A. 1.8 minutes B. 2.4 minutes C. 3.0 minutes D. 0.79 minute

A.

A 50.0-g ball traveling at 22.0 m/s is bounced off a brick wall and rebounds at 21.0 m/s. A high-speed camera records this event. If the ball is in contact with the wall for 2.50 ms, what is the average acceleration of the ball during this time interval? A. 1.72E+4 m/s2 B. 3.44E+4 m/s2 C. 8.60E+3 m/s2 D. 1.72E+1 m/s2 E. ​4.30E+1 m/s2

A.

A car is initially traveling west at 25 mph, and makes a turn north. As the car finishes the turn, its velocity is 20 mph north. It takes 3.5 seconds to complete the turn. What is the average acceleration of the car while it is turning, in mph/s? Let east be the positive-x direction and north be the positive-y direction. A. -7.1 + 5.7 B. 7.1 - 5.7 C. 5.7 - 7.1 D. -5.7 + 7.1

A.

A car is moving in the positive direction along a straight highway and accelerates at a constant rate while going from point A to point B. If the acceleration is positive, increasing the speed of the car, when does the position where the average speed equals the instantaneous speed occur during the time interval from A to B? Assume the time interval is T. A. T/2 from the start of the interval B. before T/2 from the start of the interval C. after T/2 from the start of the interval D. It depends on the speed at the start of the time interval.

A.

A jet airliner moving at 470 mph due east moves into a region where the wind is blowing at 110 mph in a direction 30.0° north of east. What is the new velocity and direction of the aircraft? A. 568 mph, 5.56° N of E B. 573 mph, 5.98° N of E C. 520 mph, 9.06° N of E D. 568 mph, 10.4° N of E E. 448 mph, 9.45° N of E

A.

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds. She then pulls the parachute cord and after a 4.00-second constant deceleration, descends at 10.5 m/s for 60.0 seconds, reaching the ground. From what height did the parachutist jump?​ A. 1.03E+3 m B. 7.88E+2 m C. 1.19E+3 m D. 1.66E+3 m ​E. 1.43E+3 m

A.

A plane is moving due north, directly towards its destination. Its airspeed is 210 mph. A constant breeze is blowing from west to east at 25.0 mph. In which direction is the plane pointed? A. 6.79° W of N B. 83.2° W of N C. 44.8° W of N D. 83.2° E of N E. 45.2° E of N

A.

A quarterback takes the ball from the line of scrimmage, runs backward for 12 yards, then sideways parallel to the line of scrimmage for 18 yards. He then throws a 47-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? A. 39 yards B. 47 yards C. 31 yards D. 62 yards E. 66 yards

A.

A rock, released at rest from the top of a tower, hits the ground after 3.5 s. What is the speed of the rock as it hits the ground? (g = 9.8 m/s2 and air resistance is negligible) A. 34 m/s B. 17 m/s C. 44 m/s D. 68 m/s ​E. 24 m/s

A.

In a two-dimensional Cartesian system, the x-component of a 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) A. dividing by cosine B. dividing by sine C. multiplying by cosine D. multiplying by sine

A.

John throws a baseball from the outfield from shoulder height, at an initial velocity of 41.5 m/s at an initial angle of 40.0° with respect to the horizontal. The ball is in its trajectory for a total interval of 5.00 s before the third baseman catches it at an equal shoulder-height level. (Assume air resistance negligible.) What is the ball's horizontal displacement?​ A. 159 m B. 267 m C. 174 m D. zero E. 495 ​m

A.

Two projectiles are launched at 100 m/s, the angle of elevation for the first being 30° and for the second 60°. Which of the following statements is false? A. Both projectiles have the same acceleration while in flight. B. The second projectile has the lower speed at maximum altitude. C. Both projectiles have the same range. D. All of the above statements are true.

A.

A Baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point is the magnitude of the acceleration at a minimum? A. At the top of the trajectory B. Acceleration is constant during entire trajectory

B.

A ball is thrown vertically upwards at 24.5 m/s. For its complete trip (up and back down to the starting position), its average speed is​ A. 18.4 m/s. B. 12.3 m/s. C. 24.5 m/s. ​D. 6.1 m/s. ​E. not given.

B.

A boat moves through the water in a river at a speed of 8 m/s relative to the water. The boat makes a trip downstream and then makes a return trip upstream to the original starting place. Which trip takes longer? A. the downstream trip B. the upstream trip C. Both trips take the same amount of time. D. The answer cannot be figured without knowing the speed of the river flow.

B.

A boat travels upstream and after one hour has gone 10 km. The boat next travels downstream and after one hour has gone 18 km. If the boat's speed relative to the water is constant, what is the speed of the current in the river? A. 3 km/h B. 4 km/h C. 5 km/h D. 6 km/h E. 7 km/h

B.

A plane is moving due north, directly towards its destination. Its airspeed is 220 mph. A constant breeze is blowing from west to east at 50 mph. How long will it take for the plane to travel 220 miles north?​ A. one hour B. more than one hour C. less than one hour D. more information is needed ​E. none of the above

B.

A projectile is launched at an angle less than 30° and at speed v. Which will increase the projectile's range more, ignoring atmospheric drag? A. doubling the launch angle B. increasing the speed of launch by 50% C. reducing the mass of the projectile D. launching on February 29th

B.

A projectile is thrown horizontally at 11.5 m/s. The projectile hits the ground 0.570 s later. What is the angle of impact the projectile makes with the horizontal ground? A. -29.1° B. -25.9° C. 119° D. -89.7° E. -64.1°

B.

A railroad train travels forward along a straight track at 90.0 m/s for 1 000 m and then travels at 70.0 m/s for the next 1 000 m. What is the average velocity? A. 79.3 m/s B. 78.8 m/s C. 83.8 m/s D. 75.8 m/s ​E. 81.5 m/s

B.

A startled deer runs 520 m at 20.0° north of east for half a minute, then turns and runs 380 m at 55.0° north of west for 15.0 seconds and stops. What is the average velocity of the deer during this time? Group of answer choices A. 14.3 m/s B. 12.4 m/s C. 20.0 m/s D. 36.1 m/s

B.

A stone is thrown with an initial speed of 11.5 m/s at an angle of 50.0 above the horizontal from the top of a 30.0-m-tall building. Assume air resistance is negligible, and g = 9.8 m/s2. What is the speed of the rock as it hits the ground? A. 11.5 m/s B. 26.8 m/s C. 24.5 m/s D. 16.2 m/s

B.

An object moves at a constant velocity of 12 m/s to the southwest for an interval of 30 s. Halfway through this interval, what is the magnitude of its instantaneous velocity?​ A. It can be any value from 0 to 24 m/s. B. 12 m/s C. 6 m/s D. More information is needed. ​E. 24 m/s

B.

An x vs. t graph is drawn for a ball moving in one direction. The graph starts at the origin and at t = 5 s the velocity of the ball is zero. We can be positive that at t = 5 s, A. the slope of the curve is non-zero. B. the ball has stopped. C. the acceleration is constant. D. the curve is at x = 0, t = 0.

B.

Jeff throws a ball straight up. For which situation is the vertical velocity zero? A. on the way up B. at the top C. on the way back down D. none of the above

B.

John throws a rock down with speed 11 m/s from the top of a 25-m tower. If g = 9.8 m/s2 and air resistance is negligible, what is the rock's speed just as it hits the ground? A. 19 m/s B. 25 m/s C. 610 m/s D. 22 m/s ​D. 12 m/s

B.

On a position-versus-time graph, the slope of the straight line joining two points on the plotted curve that are separated in time by the interval Δt, is which of the following quantities? A. average steepness B. average velocity C. instantaneous velocity D. average acceleration

B.

On a velocity-time graph for a particle, suppose the plot starts at some positive velocity and then follows a straight line to zero at a later time. Which of the following must be true about a position vs. time graph for this same time interval? A. The curve will start at a positive position value and follow a straight line to zero at the later time. B. The curve will rise steeply at first and as time goes on will level out approaching its highest position value at the later time. C. The curve will drop steeply at first and as time goes on will approach its lowest position value at the later time D. The curve will start at the zero of position and follow a straight line to its highest position at the later time.

B.

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? A. The greater mass hits the ground first. B. Both objects hit the ground together. C. The smaller mass hits the ground first. D. No conclusion can be made with the information given.

B.

A cart is given an initial velocity of 5.0 m/s and experiences a constant acceleration of 2.4 m/s2. What is the magnitude of the cart's displacement during the first 5.0 s of its motion?​ A. 35 m B. 85 m C. 55 m D. 11 m ​E. 17 m

C.

A projectile is fired at an angle of elevation of 30°. Neglecting air resistance, what are possible angles in flight between the acceleration vector and the velocity vector? A. 160° and 40° B. 20° and 70° C. 90° and 30° D. none of the above E. 10° and 30°

C.

A projectile is fired directly upwards at 49.4 m/s. A second projectile is dropped from rest at some higher elevation at the instant the first projectile is fired and passes the first projectile 3.00 s later. From the frame of reference of the first projectile, what is the velocity of the second projectile as it passes by? A. 64.1 m/s, downward B. 71.5 m/s, downward C. 49.4 m/s, downward D. 34.7 m/s, downward E. 104 m/s, downward

C.

A stone is thrown at an angle of 30° 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 4.8 s. What is the height of the cliff? (g = 9.8 m/s2 and air resistance is negligible) A. 140 m B. 110 m C. 84 m D. 29 m

C.

A stone is thrown with an initial speed of 11.5 m/s at an angle of 50.0 above the horizontal from the top of a 30.0-m-tall building. Assume air resistance is negligible, and g = 9.8 m/s2. What is the magnitude of the vertical-velocity component of the rock as it hits the ground? A. 8.81 m/s B. 7.39 m/s C. 25.8 m/s D. 19.3 m/s

C.

A strobe photograph shows equally-spaced images of a car moving along a straight road. If the time intervals between images is constant, which of the following cannot be positive? A. the speed of the car B. the average velocity of the car C. the acceleration of the car D. the direction of motion of the car

C.

A vehicle designed to operate on a drag strip accelerates from zero to 34 m/s while undergoing a straight-line path displacement of 48 m. What is the vehicle's acceleration if its value may be assumed to be constant? A. 9 m/s2 B. 6.0 m/s2 C. 12 m/s2 D. 18 m/s2 E. 24 m/s2

C.

An object moves 10 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 th e object? A. + B. − C. 0 (no sign) D. any of the above

C.

Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities? A. velocity B. average velocity C. speed D. displacement

C.

If a is acceleration, v is velocity, x is position, and t is time, then which equation is not dimensionally correct? A. t = x/v B. a = v2/x C. v = a/t D. t2 = 2x/a

C.

Plane A is flying at 350 mph in the northeast direction relative to the Earth. Plane B is flying at 460 mph in the north direction relative to the Earth. What is the direction of motion of Plane B as observed from Plane A? A. 70.7° N of E B. 49.3° N of W C. 40.7° N of W D. 19.3° N of W E. 48.2° N of E

C.

Starting from rest, a car accelerates down a straight road with constant acceleration a for a time t, then the direction of the acceleration is reversed, (i.e., it is −a), and the car comes to a stop in an additional time t, the time for the whole trip being 2t. At what time, or times, is the average velocity of the car for the trip equal to its instantaneous velocity during the trip? A. There is no such time. B. It is at the halfway point at t. C. This occurs at 2 times, 0.5t and 1.5t. D. This occurs at 2 times, 0.707t and 1.293t.

C.

Two baseballs are released at the same time. One is dropped from rest and the other is given an initial horizontal velocity. Which of the following is not true? Ignore atmospheric drag. A. Both baseballs hit the ground at the same time. B. Both have the same vertical component of velocity as they reach impact. C. The horizontal component of velocity increases at a greater rate than the vertical component of velocity for both while they are both in the air. D. The horizontally-released ball has a greater speed than the other ball for the whole trip.

C.

A hiker walks 200 m west and then walks 100 m north. In what direction is her resulting displacement? A. north B. west C. northwest D. None of the answers is correct.

D.

A rock is thrown straight up with an initial velocity of 25.0 m/s. What maximum height will the rock reach before starting to fall downward? (Take acceleration due to gravity as 9.80 m/s2.)​ A. 39.9 m B. 15.9 m C. 63.8 m D. 31.9 m ​E. 47.8 m

D.

A stone is thrown with an initial speed of 11.5 m/s at an angle of 50.0 above the horizontal from the top of a 30.0-m-tall building. Assume air resistance is negligible, and g = 9.8 m/s2. What is the magnitude of the horizontal displacement of the rock? A. 3.53 m B. 13.3 m C. 222 m D. 26.1 m

D.

At the top of a cliff 100 m high, Raoul throws a rock upward with velocity 15.0 m/s. How much later should he drop a second rock from rest so both rocks arrive simultaneously at the bottom of the cliff?​ A. 8.08 s B. 3.31 s C. 5.02 s D. 1.78 s ​E. 0.89 s

D.

Starting from rest, a car accelerates down a straight road with constant acceleration a1 for 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? A. No, because this is not a case of constant acceleration. B. Yes, use (a1 + a2)/2 as the average acceleration and the total time in the calculation. C. Yes, use a1 + a2 as the acceleration and the average time (t1 + t2)/2 in the calculation. D. Yes, break the problem up 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.

D.