Physics 1 Exam 1

A certain freely falling object, released from rest, requires 1.20 s to travel the last 27.5 m before it hits the ground. (a) Find the velocity of the object when it is 27.5 m above the ground. (Indicate the direction with the sign of your answer. Let the positive direction be upward.) (b) Find the total distance the object travels during the fall.

-17.0 m/s, 42.3 m

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

-2.08 m/s^2

A bartender slides a beer mug at 1.3 m/s towards a customer at the end of a frictionless bar that is 1.3 m tall. The customer makes a grab for the mug and misses, and the mug sails off the end of the bar. (a) How far away from the end of the bar does the mug hit the floor?0.67 m (b) What are the speed and direction of the mug at impact?

0.67 m,speed 5.2 m/s direction 75.6 ° below the horizontal

A skydiver jumps out of a hovering helicopter. A few seconds later, another skydiver jumps out, so they both fall along the same vertical line relative to the helicopter. Both skydivers fall with the same acceleration. (Assume g is constant.) The vertical distance between them 1. increases. 2. decreases. 3. stays the same.

1. increases.

A track star in the broad jump goes into the jump at 12.0m/s and launches himself at 26.0° above the horizontal. How long is he in the air before returning to Earth?

1.07 s

Which of the following is NOT true? 1.A moving car with constant acceleration can never stop and stay stopped. 2.If a car is traveling eastward, its acceleration is eastward. 3.If a car is slowing down, its acceleration must be negative. 4.If a car is speeding up, its acceleration must be greater than zero.

1.A moving car with constant acceleration can never stop and stay stopped.

Under which of the following conditions is the magnitude of the average velocity of a particle moving in one dimension smaller than the average speed over the time interval? 1.A particle moves in the +xdirection and then reverses the direction of its motion. 2.A particle moves in the -xdirection without reversing. 3.There are no conditions for which this is true. 4.A particle moves in the +xdirection without reversing.

1.A particle moves in the +xdirection and then reverses the direction of its motion.

A baseball thrown from the outfield is released from shoulder height at an initial velocity of 29.1m/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?

10.8 m

VectorA is 3.00 units in length and points along the positivexaxis; vectorBis 5.00 units in length and points along a direction 150°from the positive x-axis. What is the direction of their sum with respect to the positive x-axis?

118 degrees

Use the worked example above to help you solve this problem. An Alaskan rescue plane drops a package of emergency rations to stranded hikers, as shown in the figure. The plane is traveling horizontally at 31.0 m/s at a height of 1.15 102 m above the ground. (a) Where does the package strike the ground relative to the point at which it was released? (b) What are the horizontal and vertical components of the velocity of the package just before it hits the ground? (c) Find the angle of the impact.

150 m, horizontal 31.0 m/s vertical -47.5 m/s, -56.9 °

An automobile driver puts on the brakes and decelerates from 35.0 m/s to zero in 11.0 s. What distance does the car travel?

193 meters

The figure below shows the unusual path of a confused football player. After receiving a kickoff at his own goal, he runs downfield to within inches of a touchdown, then reverses direction and races back until he's tackled at the exact location where he first caught the ball. During this run, which took 25 s, what is the path length he travels? 1. 100 yd 2. 200 yd 3. 0.00 yd 4. It is more than 100 yd, but you must know the exact path to say exactly.

2. 200 yd

The velocity and acceleration of an object 1.must have the same sign. 2.can have opposite signs. 3.must both be zero simultaneously; one cannot be zero and the other nonzero. 4.must have opposite signs.

2.can have opposite signs.

The equations of kinematics 1.cannot be used if the acceleration is equal to zero. 2.cannot be used if the acceleration varies with time. 3.can be used in any situation. 4.None of these choices are correct.

2.cannot be used if the acceleration varies with time.

Which of the following would serve as the best time standard? 1.the rotation of Earth upon its axis 2.the vibration of a Cs-133 atom 3.a grandfather clock 4.the buzzing of a mosquito

2.the vibration of a Cs-133 atom

A plane is moving due north, directly towards its destination. Its airspeed is 210mph. A constant breeze is blowing from west to east at 20.0mph. At what rate is the plane moving north?

209 mph

A stone is thrown with an initial speed of 11.5m/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=9.8m/s^2. What is the magnitude of the vertical-velocity component of the rock as it hits the ground?

25.8m/s

A projectile is fired from ground with velocity 30 m/s with an initial angle 30.0deg. What are the horizontal and vertical components of this initial velocity ?

25.98 m/s, 15 m/s

A fireman, 57.6m away from a burning building, directs a stream of water from a firehose at an angle of 35.2° above the horizontal. If the initial speed of the stream is 42.7m/s, at what height will the stream of water strike the building?

27.3 m

Find the number of significant figures in each of the following. (a) 82.2 ± 0.4 (b) 3 ✕ 109 (c) 2.36 ✕ 10−6 (d) 0.0077

3, 1, 3, 2

How many significant figures are there in each of the following? (a) 78.6 ± 0.53 (b) 3 ✕ 1091 (c) 2.48000 ✕ 10−66 (d) 0.00222

3, 1, 6, 2

What was the player's displacement? 1. 100 yd 2. 200 yd 3. 0.00 yd 4. It is more than 100 yd, but you must know the exact path to say exactly.

3. 0.00 yd

CengageWhich of the following expresses 5.2 × 10^-5 s correctly using the metric prefixes given? 1. 520 ks 2. 0.52 ms 3. 52 mu-s 4. 52 ns

3. 52 mu-s

For the two skydivers, The difference in their velocities 1.increases. 2.decreases. 3.stays the same.

3. stays the same.

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.)

3.6 seconds

Which of the following statements is correct? 1.If an equation is dimensionally correct it must be true and if it is not dimensionally correct it may be true. 2.If an equation is dimensionally correct it may be true and if an equation is not dimensionally correct it may be true. 3.If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true. 4.If an equation is dimensionally correct it must be true and if an equation is not dimensionally correct it cannot be true.

3.If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true.

Let's say that during a thunderstorm you measure the time lag between the flash and the thunderclap to be 3 seconds. If the speed of sound is about 340 m/s, which of the following is the best estimate of your distance to the lightening bolt? 1.about 3 km 2.about 0.3 km 3.about 1 km 4.about 10 km

3.about 1 km

If a car is traveling eastward and slowing down, what is the direction of the acceleration on the car that causes it to slow down? 1. No acceleration is required to slow the car. 2.eastward 3.westward 4.None of these choices is correct.

3.westward

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/s2and air resistance is negligible)

34 m/s

During the player's run, which took 25 s, what is his average velocity in the x-direction? 1. 100 yd/s 2. 25.0 yd/s 3. 8.00 yd/s 4. 0.00 yd/s

4. 0.00 yd/s

Suppose that you measure the position of a chair using a meter stick and you record the distance of the center of the seat from the wall. Which of the following measurements is the most reasonable? 1. 1.043 860 564 2 m 2. 1.043 860 m 3. 1 m 4. 1.04 m

4. 1.04 m

Suppose that two quantities, A and B, have different dimensions. Determine which of the following arithmetic operations could be physically meaningful. (i) A + B (ii) A/B (iii) B - A (iv) AB 1.(iv) only 2.(ii) only 3.(i) and (iii) 4.(ii) and (iv)

4.(ii) and (iv)

A tennis player on serve tosses a ball straight up. While the ball is in free fall, its acceleration 1.increases. 2.decreases. 3.increases and then decreases. 4.decreases and then increases. 5.remains constant.

4.decreases and then increases.

Changing the positive direction in a reference frame to the opposite direction does not change the sign of which of the following quantities? 1.Displacement 2.Average velocity 3.Acceleration 4.speed

4.speed

A stone is thrown at an angle of 30° above the horizontal from the top edge of a cliff with an initial speed of 8.0m/s. A stop watch measures the stone's trajectory time from top of cliff to bottom to be 5.9s. How far out from the cliff's edge does the stone travel horizontally?(g=9.8m/s^2 and air resistance is negligible)

41 m

The x and y components of a vector in a horizontal plane are 4.00 m and 3.00 m, respectively. (a) What is the magnitude of this vector? (b) What angle does this vector make with the positive +y-axis.

5 m, 53.1 degree

A vector A has components Ax = −4.00 m and Ay = 3.50 m. Find the magnitude (in m) and the direction (in degrees counterclockwise from the +x-axis) of the vector.

5.3 m, 139 deg

A train slowly climbs a 400-m mountain track which is at an angle of 8.0°with respect to the horizontal. How much altitude does it gain?

55. 7 m

A ball is launched from ground level at 25m/s at an angle of 31° above the horizontal. How far does it go before it is at ground level again?

56m

A truck covers 40.0 m in 8.45 s while uniformly slowing down to a final velocity of 2.75 m/s. (a) Find the truck's original speed (b) Find its acceleration.

6.72 m/s, -0.470 m/s^2

The speed of light is about 3.00 ✕ 10^8 m/s. Convert this figure to miles per hour.

670 000 000

A drag racer starts from rest and accelerates at 8.0 m/s2for the entire distance of 300 m. What is the velocity of the race car at the end of the run?

69 m/s

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?

7.77 m/s

A helicopter is traveling at 50.0m/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=9.8m/s^2 and air resistance negligible)

74m/s

A rectangular airstrip measures 32.40 m by 240 m, with the width measured more accurately than the length. Find the area (in m2), taking into account significant figures.

7700

Each edge of a cube has a length of 12.7 cm. What is the length of a diagonal of the cube going through the center of the cube?

8.7 cm

A grasshopper jumps a horizontal distance of 1.50 m from rest, with an initial velocity at a 43.0° angle with respect to the horizontal. (a) Find the initial speed of the grasshopper. (b) Find the maximum height reached.

??

The Cartesian coordinates of a point in the xy-plane are (x,y) = (3.50 m, 2.50 m). The polar coordinate of this point is A) (r, theta) = ( 4.30 m, 35.50deg) B) (r, theta) = ( 5.30 m, -35.50deg) C) (r, theta) = ( 6.30 m, 44.50 deg) D) (r, theta) = ( 7.30 m, 180.00deg)

A) (r, theta) = ( 4.30 m, 35.50deg)

An object is freely falling due to gravity and assume no air resistance. If we assume downward motion as negative, the acceleration of that object is A) -9.80 m/s2 B)9.80 m/s2 C) can't tell D) 0 m/s2

A) -9.80 m/s2

What is 0.674/0.74 to the proper number of significant digits? A) 0.91 B) 0.9 C) 0.9108 D)0.911

A) 0.91

A car travels in straight line from 30 m to 52 m in 10 s. The average velocity of that car is A) 2.2 m/s B) 5.2 m/s C) 3.0 m/s D) 8.2 m/s

A) 2.2 m/s

Which of the following situations is impossible? A) An object has constant non-zero velocity and changing acceleration. B) An object has zero velocity but non-zero acceleration. C) An object has constant non-zero acceleration and changing velocity. D) An object has velocity directed east and acceleration directed west

A) An object has constant non-zero velocity and changing acceleration.

The slope of position vs time graph gives A) Position B) velocity C) acceleration D) time

A) Position

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? A) The acceleration is toward the east. B) The acceleration is toward the west. C) Since the car is slowing down, its acceleration must be negative. D)The acceleration is zero.

A) The acceleration is toward the east.

The acceleration of a general projectile motion in vertical motion is -9.80 m/s2. A) True B)False

A) True

Projectile motion is special case of A) two dimensional motion B) one dimensional motion C) three dimensional motion D) can't tell

A) two dimensional motion

The vertical component of velocity (vy) of projectile fired from the ground at its maximum height is A) zero B) maximum C) minimum D) none of the above

A) zero

If v and v0 are the final and initial velocity, a is acceleration, and t is time, then the equation v = v0+ at is dimensionally correct. A)True B) False

A)True

Which of the following physical quantity is not a fundamental quantity ? A) Volume B) Mass C) Length D) Time

A)Volume

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

At the top

Write out the 7.35 x 10^-5 in full with a decimal point and correct number of zeros. A) 0.00000735 B) 0.0000735 C) 0.000735 D) 0.00735 E) 0.0735

B) 0.0000735

A ranch has a fenced rectangular area of length 750 m and width 125 m. The area of rectangular fenced in correct number of significant figures is A)9.38 x 10^4 m^2 B) 9.4 x 10^4 m^2 C) 9.375 x 10^4 m^2 D) 9.3750 x 10^4 m^2

B) 9.4 x 10^4 m^2

A car must always have an acceleration in same direction as its velocity. A) True B) False

B) False

A student throws a heavy red ball horizontally from a balcony of a tall building with an initial speed v0. At the same time, a second student drops a lighter blue ball from the same balcony. Neglecting air resistance, which statement is true? A) The blue ball reaches the ground first. B) The balls reach the ground at the same instant. C) The red ball reaches the ground first. D) Both balls hit the ground with the same speed. E) None of the above statements are true.

B) The balls reach the ground at the same instant.

Any point in Cartesian coordinate system can be converted in to polar coordinate system using trigonometry. A) False B) True C) Can't tell D) Sometimes can convert

B) True

For general projectile motion with no air resistance, the horizontal component of a projectile's velocity A) continuously increases. B) remains constant. C) continuously decreases. D) remains zero. E) first decreases and then increases.

B) remains constant.

Displacement is a vector quantity while distance is a A) SI unit B) scalar C) can't say D) none of these

B) scalar

A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the level ground below if neither of them experiences any air resistance? A) It is impossible to tell because we do not know their masses. B) the ball C) the stone D) Both are traveling at the same speed.

B) the ball

What is the dimension of velocity ? A)𝐿 B) 𝐿/𝑇 C) 𝐿^2/𝑇^2 D) 𝐿𝑀^2𝑇

B) 𝐿/𝑇

The magnitudes of two vector AandB are 12 units and 8 units, respectively. What are the largest and smallest possible values for the magnitude of the resultant vector R =A +B ? A) 14.4 and 4 B) 12 and 8 C) 20 and 4 D) none of these

C) 20 and 4

A car travels from initial velocity of 10 m/s to final velocity of 20 m/s in 2 s. The acceleration of this car is A) -5 m/s2 B) 15 m/s2 C) 5 m/s2 D) -15 m/s2

C) 5 m/s2

What is the sum of 1.53 + 2.786 + 3.3 written in correct number of significant figures ? A) 7.6160 B) 8 C) 7.6 D) 7.62

C) 7.6

A baseball is thrown from the outfield toward the catcher. When the ball reaches its highest point, which statement is true? A) Its velocity is not zero, but its acceleration is zero. B) Its velocity and its acceleration are both zero. Its velocity is perpendicular to its acceleration. C) Its acceleration depends on the angle at which the ball was thrown. D) None of the above statements are true.

C) Its acceleration depends on the angle at which the ball was thrown.

The slope of velocity vs time graph gives A) Position B) velocity C) acceleration D) time

C) acceleration

As a projectile moves in its parabolic path, the velocity and acceleration vectors are perpendicular to each other at which of the following along the projectile's path? A) not enough information B) everywhere C) at the peak D) nowhere

C) at the peak

The acceleration of a general projectile motion fired from the ground along horizontal direction (ax) is A) maximum B) minimum C) zero D) g = 9,8 m/s2

C) zero

A racing car starting from rest accelerate at a constant acceleration of 5 m/s2. What is the velocity of the car after it has travelled 30.5 m? A)20.4 m/s B)10.5 m/s C)17.5 m/s D)0 m/s

C)17.5 m/s

How many physical quantities are included in fundamental SI unit ? A)3 B)5 C)7 D)9

C)7

The correct conversion of 15.0 inch length of stick in centimeters is (1 inch = 2.54 cm) A) 50.5 cm B) 35.5 cm C)42.225 cm D) 38.1 cm

D) 38.1 cm

A 10-kg rock and a20-kg rock are dropped at the same time and experience no significant air resistance. If the 10-kg rock falls with acceleration a, what is the acceleration of the 20-kg rock? A) a/2 B) 4a C) 2a D) a E) a/4

D) a

A car must always have an acceleration in the same direction as its velocity. True or False

False

Suppose the displacement x of another object is related to time t according to x = A sin(2𝜋ft), where A and f are constants. What are the dimensions of A? (Hint: A trigonometric function appearing in an equation must be dimensionless.) -L -L/T -T -T/L -L × T

L

Suppose that the displacement x of an object is related to time t according to the expression x = Bt2. What are the dimensions of B? -L × T2 -L -T -L2/L -L/T -T2/L -L/T2

L/T2

As a projectile moves in its path, is there any point along the path where the velocity and acceleration vectors are parallel to each other? (Assume the object is thrown upward and forward, but not straight up.) Yes or No

No

Use the rules for significant figures to find the answer to the addition problem S = 19.4 + 11 + 12.67 + 4.103.

S=47

An object with constant nonzero acceleration can never stop and remain at rest. True or False

True

It's possible for a slowing car to have a positive acceleration. True or False

True

As a projectile moves in its path, is there any point along the path where the velocity and acceleration vectors are perpendicular to each other? (Assume the object is thrown upward and forward, but not straight up.) Yes or No

Yes

On an interstate highway in a rural region of Wyoming, a car is traveling at a speed of 38.0 m/s. Is the driver exceeding the speed limit of 75.0 mi/h?

Yes

A European sports car dealer claims that his car will accelerate at a constant rate from rest to 100km/hr in 8.00s. If so , what is the acceleration?(Hint: First convert speed to m/s.). 100km/hr = 27.7778 m/s. a=(v_f-v_i)/t.

a= 3.47 seconds

A projectile is launched with speed v0 at an angle 𝜃0 above the horizon. Its motion is described in terms of position, velocity, and acceleration: x, y, vx, vy, ax, ay, respectively. Which are equal to zero throughout the motion? Ignore any effects of air resistance. (Select all that apply.) x y vx vy ax ay

ax

Find the sum of the following two vectors: (i) 50 units due east and (ii) 100 units 30°south of west. a) 100 units 30 degrees south of west b) 62 units 54 degrees south of west c) 87 units 60 degrees south of west d) 62 units 15 degrees south of west

b) 62 units 54 degrees south of west

A scalar quantity has ______________, but no ______________

magnitude, direction

A vector quantity is characterized by having both a _____________ and a _____________

magnitude, direction

The Cartesian coordinates of a point in the xyplane are (x, y) = (-3.50, -2.50) m as shown in the figure. Find the polar coordinates of this point.

r=4.3, theta= 216 degrees

A projectile is launched with speed v0 at an angle 𝜃0 above the horizon. Its motion is described in terms of position, velocity, and acceleration: x, y, vx, vy, ax, ay, respectively. Which of those quantities are constant during the motion? (Select all that apply.) x y vx vy ax ay

vx, ax, ay

Calculate the x-component and the y-component (in m) of the vector with magnitude 26.0 m and direction 50.0°.

x= 17 y= 20

A projectile is launched at some angle to the horizontal with some initial speed vi, and air resistance is negligible. (a) Is the projectile a freely falling body? Yes or No (b) What is its acceleration in the vertical direction? (Let up be the positive direction.) (c) What is its acceleration in the horizontal direction?

yes, -9.8 m/s2, 0.0 m/s2