physics chapter 2

A car travels in a straight line covering a total distance of 90.0 miles in 60.0 minutes. Which one of the following statements concerning this situation is necessarily true? (a) The velocity of the car is constant. (b) The acceleration of the car must be non-zero. (c) The first 45 miles must have been covered in 30.0 minutes. (d) The speed of the car must be 90.0 milesperhour throughout the entire trip. (e) The average velocity of the car is 90.0 miles per hour in the direction of motion.

The average velocity of the car is 90.0 miles per hour in the direction of motion.

An object moving along a straight line is decelerating. Which one of the following statements concerning the object's acceleration is necessarily true? (a) The value of the acceleration is positive. (b) Thedirectionoftheaccelerationisinthesamedirectionasthedisplacement. (c) An object that is decelerating has a negative acceleration. (d) Thedirectionoftheaccelerationisinthedirectionoppositetothatofthevelocity. (e) The acceleration changes as the object moves along the line.

The direction of the acceleration is in the direction opposite to that of the velocity.

Which one of the following is not a vector quantity? (a) acceleration (c) displacement (e) instantaneous velocity (b) average speed (d) average velocity

average speed

A brick is dropped from rest from a height of 4.9 m. How long does it take the brick to reach the ground? (a) 0.6s (c) 1.2s (e) 2.0s (b) 1.0s (d) 1.4s

1.0 s

During the first 18 minutes of a 1.0-hour trip, a car has an average speed of 11 m/s. What must the average speed of the car be during the last 42 minutes of the trip be if the car is to have an average speed of 21 m/s for the entire trip? (a) 21 m/s (c) 25 m/s (e) 29 m/s (b) 23m/s (d) 27m/s

25 m/s

The minimum takeoff speed for a certain airplane is 75 m/s. What minimum acceleration is required if the plane must leave a runway of length 950 m? Assume the plane starts from rest at one end of the runway. (a) 1.5 m/s2 (c) 4.5 m/s2 (e) 7.5 m/s2 (b) 3.0 m/s2 (d) 6.0 m/s2

3.0 m/s2

At time t = 0 s, an object is observed at x = 0 m; and its position along the x axis follows this expression: x = -3t +t3, where the units for distance and time are meters and seconds, respectively. What is the object's displacement ∆x between t = 1.0 s and t = 3.0 s? (a) +20m (c) +10m (e) -2m (b) -20m (d) +2m

+20m

Carl Lewis set a world record for the 100.0-m run with a time of 9.86 s. If, after reaching the finish line, Mr. Lewis walked directly back to his starting point in 90.9 s, what is the magnitude of his average velocity for the 200.0 m? (a) 0 m/s (c) 1.98 m/s (e) 10.1 m/s (b) 1.10m/s (d) 5.60m/s

0m/s

A ball is thrown vertically upward from the surface of the earth. Consider the following quantities: (1) the speed of the ball; (2) the velocity of the ball; (3) the acceleration of the ball. Which of these is (are) zero when the ball has reached the maximum height? (a) 1 and 2 only (c) 1only (e) 1,2,and3 (b) 1 and 3 only (d) 2 only

1 and 2 only

A train passes through a town with a constant speed of 16 m/s. After leaving the town, the train accelerates at 0.33 m/s2 until it reaches a speed of 35 m/s. How far did the train travel while it was accelerating? (a) 0.029 km (c) 1.5 km (e) 3.0 km (b) 0.53 km (d) 2.3 km

1.5 km`

A car is moving at a constant velocity when it is involved in a collision. The car comes to rest after 0.450 s with an average acceleration of 65.0 m/s2 in the direction opposite that of the car's velocity. What was the speed, in km/h, of the car before the collision? (a) 29.2 km/h (c) 80.5 km/h (e) 144 km/h (b) 44.8 km/h (d) 105 km/h

105 km/h

A train approaches a small town with a constant velocity of +28.6 m/s. The operator applies the brake, reducing the train's velocity to +11.4 m/s. If the average acceleration of the train during braking is -1.35 m/s2, for what elapsed time does the operator apply the brake? (a) 8.44 s (c) 3.38 s (e) 10.4 s (b) 12.7s (d) 5.92s

12.7 s

Elijah throws a tennis ball vertically upward. The ball returns to the point of release after 3.5 s. What is the speed of the ball as it is released? (a) 0m/s (c) 17m/s (e) 34m/s (b) 14m/s (d) 21m/s

17 m/s

A car, starting from rest, accelerates in a straight-line path at a constant rate of 2.5 m/s2. How far will the car travel in 12 seconds? (a) 180m (c) 30m (e) 4.8m (b) 120m (d) 15m

180 m

An elevator is moving upward with a speed of 11 m/s. Three seconds later, the elevator is still moving upward, but its speed has been reduced to 5.0 m/s. What is the average acceleration of the elevator during the 3.0 s interval? (a) 2.0 m/s2, upward (c) 5.3 m/s2, upward (e) 2.7 m/s2, downward (b) 2.0 m/s2, downward (d) 5.3 m/s2, downward

2.0 m/s2 downward

Carole's hair grows with an average speed of 3.5 × 10−9 m/s. How long does it take her hair to grow 0.30m? Note:1yr=3.156×107 s. (a) 1.9 yr (c) 0.37 yr (e) 2.7 yr (b) 1.3 yr (d) 5.4 yr

2.7 years

A car is initially traveling at 50.0 km/h. The brakes are applied and the car stops over a distance of 35 m. What was magnitude of the car's acceleration while it was braking? (a) 2.8 m/s2 (c) 36 m/s2 (e) 9.8 m/s2 (b) 5.4 m/s2 (d) 71 m/s2

2.8 m/s2

A cheetah is walking at a speed of 1.10 m/s when it observes a gazelle 41.0 m directly ahead. If the cheetah accelerates at 9.55 m/s2, how long does it take the cheetah to reach the gazelle if the gazelle doesn't move? (a) 4.29 s (c) 3.05 s (e) 2.82 s (b) 3.67s (d) 1.94s

2.82 s

A car is stopped at a red traffic light. When the light turns to green, the car has a constant acceleration and crosses the 9.10-m intersection in 2.47 s. What is the magnitude of the car's acceleration? (a) 1.77 m/s2 (c) 3.60 m/s2 (e) 9.80 m/s2 (b) 2.98 m/s2 (d) 7.36 m/s2

2.98 m/s2

Water drips from rest from a leaf that is 20 meters above the ground. Neglecting air resistance, what is the speed of each water drop when it hits the ground? (a) 30 m/s (c) 40 m/s (e) 20 m/s (b) 15m/s (d) 10m/s

20 m/s

A turtle takes 3.5 minutes to walk 18 m toward the south along a deserted highway. A truck driver stops and picks up the turtle. The driver takes the turtle to a town 1.1 km to the north with an average speed of 12 m/s. What is the magnitude of the average velocity of the turtle for its entire journey? (a) 3.6 m/s (c) 6.0 m/s (e) 11 m/s (b) 9.8m/s (d) 2.6m/s

3.6 m/s

In the process of delivering mail, a postal worker walks 161 m, due east from his truck. He then turns around and walks 194 m, due west. What is the worker's displacement relative to his truck? (a) 33 m, due west (c) 194 m, due west (e) 355 m, due west (b) 33m,dueeast (d) 252m,dueeast

33m due west

When the outdoor emergency warning siren at Cheryl's school was tested, the sound from the siren took 7.0 s to reach her house located 2.40 km from the school. What is the speed of sound in air? (a) 240 m/s (c) 440 m/s (e) 640 m/s (b) 340m/s (d) 540m/s

340 m/s

A rock is dropped from rest from a height h above the ground. It falls and hits the ground with a speed of 11 m/s. From what height should the rock be dropped so that its speed on hitting the ground is 22 m/s? Neglect air resistance. (a) 1.4h (c) 3.0h (e) 0.71h (b) 2.0h (d) 4.0h

4.0 h

A body initially at rest is accelerated at a constant rate for 5.0 seconds in the positive x direction. If the final speed of the body is 20.0 m/s, what was the body's acceleration? (a) 0.25 m/s2 (c) 4.0 m/s2 (e) 1.6 m/s2 (b) 2.0 m/s2 (d) 9.8 m/s2

4.0 m/s2

A landing airplane makes contact with the runway with a speed of 78.0 m/s and moves toward the south. After 18.5 seconds, the airplane comes to rest. What is the average acceleration of the airplane during the landing? (a) 2.11 m/s2, north (c) 4.22 m/s2, north (e) 14.3 m/s2, north (b) 2.11 m/s2, south (d) 4.22 m/s2, south

4.22 m/s2 north

A ball is dropped from rest from a tower and strikes the ground 125 m below. Approximately how many seconds does it take the ball to strike the ground after being dropped? Neglect air resistance. (a) 2.50 s (c) 5.05 s (e) 16.0 s (b) 3.50s (d) 12.5s

5.05 s

A bus leaves New York City, takes a non-direct route and arrives in St. Louis, Missouri 23 hours, 16 minutes later. If the distance between the two cities is 1250 km, what is the magnitude of the bus' average velocity? (a) 37.2 km/h (c) 46.0 km/h (e) 58.1 km/h (b) 41.4 km/h (d) 53.7 km/h

53.7 km/h

A car starts from rest and accelerates at a constant rate in a straight line. In the first second the car covers a distance of 2.0 meters. How much additional distance will the car cover during the second second of its motion? (a) 2.0m (c) 6.0m (e) 13m (b) 4.0 m (d) 8.0 m

6.0 m

Neglecting air resistance, what maximum height will be reached by a stone thrown straight up with an initial speed of 35 m/s? (a) 98m (c) 41m (e) 18m (b) 160m (d) 63m

63 m

A car traveling along a road begins accelerating with a constant acceleration of 1.5 m/s2 in the direction of motion. After traveling 392 m at this acceleration, its speed is 35 m/s. Determine the speed of the car when it began accelerating. (a) 1.5 m/s (c) 34 m/s (e) 2.3 m/s (b) 7.0m/s (d) 49m/s

7.0 m/s

A Canadian goose flew 845 km from Southern California to Oregon with an average speed of 30.5 m/s. How long, in hours, did it take the goose to make this journey? (a) 27.7 h (c) 66.1 h (e) 7.70 h (b) 8.33 h (d) 462 h

7.70 h

A car starts from rest and accelerates at a constant rate in a straight line. In the first second the car covers a distance of 2.0 meters. How fast will the car be moving at the end of the second second? (a) 4.0 m/s (c) 2.0 m/s (e) 8.0 m/s (b) 16m/s (d) 32m/s

8.0 m/s

A 5.0-kg rock is dropped from rest down a vertical mine shaft. How long does it take for the rock to reach a depth of 79 m? Neglect air resistance. (a) 2.8s (c) 4.9s (e) 4.0s (b) 9.0 s (e) 8.0 s

8.0 s

A racecar has a speed of 80 m/s when the driver releases a drag parachute. If the parachute causes a deceleration of -4 m/s2, how far will the car travel before it stops? (a) 20m (c) 400m (e) 1000m (b) 200 m (d) 800 m

800 m

A pitcher delivers a fast ball with a velocity of 43 m/s to the south. The batter hits the ball and gives it a velocity of 51 m/s to the north. What was the average acceleration of the ball during the 1.0 ms when it was in contact with the bat? (a) 4.3 × 104 m/s2, south (c) 9.4 × 104 m/s2, north (e) 7.0 × 103 m/s2, north (b) 5.1 × 104 m/s2, north (d) 2.2 × 103 m/s2, south

9.4 x 10^4 m/s2

Which one of the following situations is not possible? (a) A body has zero velocity and non-zero acceleration. (b) Abodytravelswithanorthwardvelocityandanorthwardacceleration. (c) A body travels with a northward velocity and a southward acceleration. (d) Abodytravelswithaconstantvelocityandatime-varyingacceleration. (e) A body travels with a constant acceleration and a time-varying velocity.

A body travels with a constant velocity and a time-varying acceleration.

Starting from rest, a particle that is confined to move along a straight line is accelerated at a rate of 5.0 m/s2. Which statement concerning the slope of the position versus time graph for this particle is true? (a) The slope has a constant value of 5.0 m/s. (b) The slope has a constant value of 5.0m/s2. (c) The slope is both constant and negative. (d) The slope is not constant and increases with increasing time. (e) The slope is not constant and decreases with increasing time.

The slope is not constant and increases with increasing time.

In which one of the following cases is the displacement of the object directly proportional to the elapsed time? (a) a ball rolls with constant velocity (b) a ball at rest is given a constant acceleration (c) a ball rolling with velocity v0 is given a constant acceleration (d) a bead falling through oil experiences a decreasing acceleration (e) a rocket fired from the earth's surface experiences an increasing acceleration

a ball rolls with constant velocity

Which one of the following statements must be true if the expression x = v0t + 12 at2 is to be used? (a) x is constant. (c) t is constant. (e) Both v0 and t are constant. (b) v is constant. (d) a is constant.

a is constant

Ball A is dropped from rest from a window. At the same instant, ball B is thrown downward; and ball C is thrown upward from the same window. Which statement concerning the balls after their release is necessarily true if air resistance is neglected? (a) At some instant after it is thrown, the acceleration of ball C is zero. (b) All three balls strike the ground at the same time. (c) All three balls have the same velocity at any instant. (d) All three balls have the same acceleration at any instant. (e) All three balls reach the ground with the same velocity.

all three balls have the same acceleration at any instant

Two cars travel along a level highway. It is observed that the distance between the cars is increasing. Which one of the following statements concerning this situation is necessarily true? (a) The velocity of each car is increasing. (b) Atleastoneofthecarshasanon-zeroacceleration. (c) The leading car has the greater acceleration. (d) Thetrailingcarhasthesmalleracceleration. (e) Both cars could be accelerating at the same rate.

both cars could be accelerating at the same rate

Two objects A and B accelerate from rest with the same constant acceleration. Object A accelerates for twice as much time as object B, however. Which one of the following statements is true concerning these objects at the end of their respective periods of acceleration? (a) Object A will travel twice as far as object B. (b) Object A will travel four times as far as object B (c) Object A will travel eight times further than object B. (d) ObjectAwillbemovingfourtimesfasterthanobjectB. (e) Object A will be moving eight times faster than object B.

object A will travel four times as far as object B

A rock is thrown vertically upward from the surface of the earth. The rock rises to some maximum height and falls back toward the surface of the earth. Which one of the following statements concerning this situation is true if air resistance is neglected? (a) As the ball rises, its acceleration vector points upward. (b) The ball is a freely falling body for the duration of its flight. (c) The acceleration of the ball is zero when the ball is at its highest point. (d) The speed of the ball is negative while the ball falls back toward the earth. (e) The velocity and acceleration of the ball always point in the same direction.

the ball is a freely falling body for the duration of its flight

In which one of the following situations does the car have a westward acceleration? (a) The car travels westward at constant speed. (b) Thecartravelseastwardandspeedsup. (c) The car travels westward and slows down. (d) The car travels eastward and slows down. (e) The car starts from rest and moves toward the east.

the car travels eastward and slows down

Starting from rest, a particle confined to move along a straight line is accelerated at a rate of 5.0 m/s2. Which one of the following statements accurately describes the motion of this particle? (a) The particle travels 5.0 m during each second. (b) Theparticletravels5.0monlyduringthefirstsecond. (c) The speed of the particle increases by 5.0 m/s during each second. (d) The acceleration of the particle increases by 5.0m/s2 during each second. (e) The final speed of the particle will be proportional to the distance that the particle covers.

the speed of the particle increases by 5.0m/s during each second