PHY 201- Exam 1

A person jogs eight complete laps around a 400-m track in a total time of 14.5 min calculate the average velocity in m/s

0m/s

A boat's speed in still water is vBW = 1.80 m/s . The boat is to travel north directly across a river (Figure 1) whose westward current has speed vWS = 1.20 m/s . Determine the speed of the boat with respect to the shore.

1.34 m/s

Captain John Stapp pioneered research into the physiological effects of large accelerations on humans. During one such test his sled slowed from 282 m/s with an acceleration of -201 m/s2. how long did it take him to stop

1.4 s

The cliff divers of Acapulco push off horizontally from rock platforms about h = 42 m above the water, but they must clear rocky outcrops at water level that extend out into the water L = 4.6 m from the base of the cliff directly under their launch point What minimum pushoff speed is necessary to clear the rocks? how long are they in the air

1.6 m/s 2.9 s

A car moving in a straight line starts at x = 0 at t = 0. It passes the point x1 = 30.0 m with a speed of 11.0 m/s at t = 3.00 s . It passes the point x2 = 385 m with a speed of 40.0 m/s at t = 20.0 s. Find the average acceleration between t = 3.00 s and t = 20.0 s

1.71 m/s2

A 5.0-kg stone is thrown upward at 7.5 m/s at an angle of 51° above the horizontal from the upper edge of a cliff, and it hits the ground 1.5 s later with no air resistance. Find the magnitude of its velocity vector just as it reaches the ground.

10 m/s

If Vx= 5.70 units and V= -8.90 units, determine the magnitude of V→. determine the direction of V ->

10.6 units 57.4 degrees below the positive x axis

Two locomotives approach each other on parallel tracks. Each has a speed v = 150 km/h with respect to the ground. If they are ddd = 8.5 km initially apart, how long will it be before they reach each other?

100s

If Vx = 9.5 units and Vy= -6.6 units, determine the magnitude of V→. determine the direction of V ->

11.6 units 34.8 degrees below the positive x axis

A car slows down uniformly from a speed of 30.0 m/s to rest in 7.40 s how far did it travel in that time

111 m

A ball player catches a ball 3.13 s after throwing it vertically upward. what height did it reach

12.0 m

A ball thrown horizontally at 12.4 m/s from the roof of a building lands 20.8 m from the base of the building. how tall is the building

13.8 m

Arlene is to walk across a "high wire" strung horizontally between two buildings 15.0 m apart. The sag in the rope when she is at the midpoint is 10.0 ∘, as shown in the figure(Figure 1). If her mass is 49.0 kg , what is the tension in the rope at this point?

1380 N

A plane has an airspeed of 142 m/s. A 16 m/s wind is blowing southward at the same time as the plane is flying. If the velocity of the plane relative to the ground is directly eastward, what is the magnitude of that velocity?

141 m/s

A ball player catches a ball 3.13 s after throwing it vertically upward. With what speed did he throw it At what did it reach

15.3 m/s 11.94 m ish

You are given a vector in the xy plane that has a magnitude of 84.0 units and a y component of -61.0 units. Assuming the x component is known to be positive, specify the magnitude of the vector which, if you add it to the original one, would give a resultant vector that is 80.0 units long and points entirely in the −x direction.

151 units

A softball is hit over a third baseman's head with some speed v0 at an angle θtheta above the horizontal. Immediately after the ball is hit, the third baseman turns around and begins to run at a constant velocity V=7.00m/s. He catches the ball t=2.00s later at the same height at which it left the bat. The third baseman was originally standing L=18.0 from the location at which the ball was hit. Find v0 Use g=9.81m/s2 for the magnitude of the acceleration due to gravity.

18.8 m/s

How many centimeters are there in a length 78.1 inches?

198 cm

A football is kicked at ground level with a speed of 18.3 m/s at an angle of 42.3 ∘ to the horizontal. How much later does it hit the ground?

2.51 s

A car moving in a straight line starts at x = 0 at t = 0. It passes the point x1 = 30.0 m with a speed of 11.0 m/s at t = 3.00 s . It passes the point x2 = 385 m with a speed of 40.0 m/s at t = 20.0 s. Find the average velocity between t = 3.00 s and t = 20.0 s.

20.9 m/s

A fire hose held near the ground shoots water at a speed of 5.8 m/s At what angle(s) should the nozzle point in order that the water land 2.5 mm away

23 67

You are given a vector in the xy plane that has a magnitude of 84.0 units and a y component of -61.0 units. Specify the direction of the vector.

23.9 above the -x axis

A shot-putter throws the "shot" (mass = 7.3 kg) with an initial speed of 14.9 m/sm/s at a 38.0 ∘ angle to the horizontal. Calculate the horizontal distance traveled by the shot if it leaves the athlete's hand at a height of 2.10 m above the ground.

24.4 m

A light plane must reach a speed of 39 m/s for takeoff. how long a runway is needed if the (constant) acceleration is 3.1 m/s2?

250 m

When an archerfish is hunting, its body shape allows it to swim very close to the water surface and look upward without creating a disturbance. The fish can then bring the tip of its mouth close to the surface and shoot the drops of water at the insects resting on overhead vegetation or floating on the water surface. At what speed v should an archerfish spit the water to shoot down an insect floating on the water surface located at a distance 0.800 m from the fish? Assume that the fish is located very close to the surface of the pond and spits the water at an angle 60∘ above the water surface.

3.01 m/s

A person jogs eight complete laps around a 400-m track in a total time of 14.5 min calculate the average speed in m/s

3.68 m/s

A softball is hit over a third baseman's head with some speed v0 at an angle θtheta above the horizontal. Immediately after the ball is hit, the third baseman turns around and begins to run at a constant velocity V=7.00m/s. He catches the ball t=2.00s later at the same height at which it left the bat. The third baseman was originally standing L=18.0 from the location at which the ball was hit. Find the angle θ theta in degrees.

31.5

You are driving home from school steadily at 98 km/h for 190 km. It then begins to rain and you slow to 63 km/h instantly. You arrive home after driving 4.0 hours. how far is your hometown from school

320 km

A car is driven 250 km west and then 98 km southwest (45∘). What is the displacement of the car from the point of origin (magnitude)? What is the displacement of the car from the point of origin (direction)?

327 km 12.2 south of west

The pulley in (Figure 1) is suspended by a cord CC. Suppose that m1 = 1.1 kg and m2 = 3.5 kg . Determine the tension in the cord that supports the pulley C after the masses are released and before one hits the ground. Ignore the mass of the pulley and cords.

33N

A cannonball is fired horizontally from the top of a cliff. The cannon is at height H= 90.0 m above ground level, and the ball is fired with initial horizontal speed v0. Assume acceleration due to gravity to be g = 9.80 m/s2 Given that the projectile lands at a distance D = 150 mm from the cliff, as shown in the figure, find the initial speed of the projectile, v0.

35 m/s

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure Determine the distance X of point P from the base of the vertical cliff.

384 m

A child is riding in a child-restraint chair, securely fastened to the seat of a car. Assume the car has speed 42 km/h when it hits a tree and is brought to rest in 0.20 s. The mass of the child is 19 kg Assuming constant deceleration during the collision, estimate the net horizontal force FF that the straps of the restraint chair exert on the child to hold her in the chair.

-1100 N

A rolling ball moves from x1 = 8.0 cm to x2 = -4.8 cm during the time from t1 = 3.9 s to t2 = 6.4 s what is the velocity in cm/s

-5.1 cm/s

What average force is required to stop a 1800 kg car in 9.0 s if the car is traveling at 90 km/h ?

-5000 N

You are given a vector in the xy plane that has a magnitude of 84.0 units and a y component of -61.0 units. What are the two possibilities for its xxx component?

-57.7 and 57.7

Vector 1V→1 is 6.6 units long and points along the negative x axis. Vector 2V→2 is 8.3 units long and points at 35 ∘ to the positive x axis. What are the x and y components of vector V→1?

-6.6 , 0

A wet bar of soap slides down a ramp 7.4 m long inclined at 8.0∘ How long does it take to reach the bottom? Assume μk = 0.070.

4.6

Ilya and Anya each can run at a speed of 8.00 mph and walk at a speed of 3.30 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half. find anya's average speed

4.67 miles

Vector 1V→1 is 6.6 units long and points along the negative x axis. Vector 2V→2 is 8.3 units long and points at 35 ∘ to the positive x axis. Determine the magnitude and angle of the sum

4.8 88 counter clockwise from the positive x axis

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure At the instant just before the projectile hits point P, find the horizontal and the vertical components of its velocity.

43.4 -56.4 m/s

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure Find the maximum height above the cliff top reached by the projectile.

47.2 m

A boy throws a ball with an initial velocity of 25 m/s at an angle of 30° above the horizontal. If air resistance is negligible, how high above the projection point is the ball after 2.0 s?

5.4 m

An airplane travels 2080 km at a speed of 720 km/h and then encounters a tailwind that boosts its speed to 990 km/h for the next 2630 km. What was the total time for the trip? What was the average speed of the plane for this trip?

5.55 h 849 km/h

Ilya and Anya each can run at a speed of 8.00 mph and walk at a speed of 3.30 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half. now find ilya's average speed

5.65 mph

A stone is thrown vertically upward with a speed of 14.8 m/s from the edge of a cliff 75.0 m high. How much later does it reach the bottom of the cliff? What is its speed just before hitting? What total distance did it travel?

5.70 s 41.1 m/s 97.4 m

A helicopter is ascending vertically with a speed of 5.22 m/s . At a height of 135 m above the Earth, a package is dropped from the helicopter. How much time does it take for the package to reach the ground? [Hint: What is v0 for the package?]

5.81 s

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure At the instant just before the projectile hits point PP, find the angle made by the velocity vector with the horizontal.

52.4

Ilya and Anya each can run at a speed of 8.00 mph and walk at a speed of 3.30 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half. how long does it take ilya to cover the distance

53.1 minutes

A car traveling 89 km/h is 290 m behind a truck traveling 71 km/h. How long will it take the car to reach the truck?

58 s

Vector 1V→1 is 6.6 units long and points along the negative x axis. Vector 2V→2 is 8.3 units long and points at 35 ∘ to the positive x axis. What are the x and y components of vector V→2?

6.8 4.8

Which projectile spends more time in the air, the one fired from 30∘ or the one fired from 60∘? (problem 14)

60

Ilya and Anya each can run at a speed of 8.00 mph and walk at a speed of 3.30 mph . They set off together on a route of length 5.00 miles . Anya walks half of the distance and runs the other half, while Ilya walks half of the time and runs the other half. how long does it take anya to cover the distance of 5 miles

64.2 mins

A cannonball is fired horizontally from the top of a cliff. The cannon is at height H= 90.0 m above ground level, and the ball is fired with initial horizontal speed v0. Assume acceleration due to gravity to be g = 9.80 m/s2 Assume that the cannon is fired at time t=0 and that the cannonball hits the ground at time tg. What is the y position of the cannonball at the time tg/2?

67.5 m

A cannonball is fired horizontally from the top of a cliff. The cannon is at height H= 90.0 m above ground level, and the ball is fired with initial horizontal speed v0. Assume acceleration due to gravity to be g = 9.80 m/s2 What is the y position of the cannonball when it is at distance D/2 from the hill? If you need to, you can use the trajectory equation for this projectile, which gives y in terms of x directly:

67.5 m

A hobbyist launches a projectile from ground level on a horizontal plain. It reaches a maximum height of 72.3 m and lands 111 m from the launch point, with no appreciable air resistance. What was the angle of launch if g = 9.80 m/s2?

69

Vector has a magnitude of 6.0 m and points 30° south of east. Vector has a magnitude of 4.0 m and points 30° west of south. The resultant vector + is given by

7.2 m at an angle of 64 south of east

A bird can fly 25 km/h how long does it take to fly 3 km

7.2 mins

A sprinter accelerates from rest to 9.00 m/s in 1.23 s. what is her acceleration in m/s2 what is her acceleration in km/h2

7.32 m/s2 9.48x10^4 km/h2

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure At the instant just before the projectile hits point PP, find the magnitude of the velocity.

71.2 m/s

A baseball is hit with a speed of 30 m/s at an angle of 45.0∘. It lands on the flat roof of a 13.0-m-tall nearby building. If the ball was hit when it was 1.0 m above the ground, what horizontal distance does it travel before it lands on the building?

77.6 m

A stone is dropped from the top of a cliff. It is seen to hit the ground below after 3.98 s how high is the cliff

77.6 m

The archerfish spits at land-based insects to cause them to fall into the water, where they are easy prey. If the archerfish spits its water 45 degrees from the horizontal aiming at an insect 2 m above the surface of the water, how fast must the fish spit the water to hit its target? The insect is at the highest point of the trajectory of the spit water. Use g = 10 m/s2

8.9 m/s

You are driving home from school steadily at 98 km/h for 190 km. It then begins to rain and you slow to 63 km/h instantly. You arrive home after driving 4.0 hours. what was your average speed

80 km/h

A 29-kg chandelier hangs from a ceiling on a vertical 4.0-m-long wire. What horizontal force would be necessary to displace its position 0.13 m to one side? What will be the tension in the wire?

9.2 N 280 N

A 0.140-kg baseball traveling 38.0 m/s strikes the catcher's mitt, which, in bringing the ball to rest, recoils backward 11.0 cm . What was the average force applied by the ball on the glove?

919 N

The magnitude of a component of a vector must be A. less than or equal to the magnitude of the vector. B. equal to the magnitude of the vector. C. greater than or equal to the magnitude of the vector. D. less than, equal to, or greater than the magnitude of the vector.

A

At time t=0 an object is traveling to the right along the +x+x axis at a speed of 10.0 m/sm/s with acceleration -2.0 m/s2. Which statement is true? A. The object will slow down, eventually coming to a complete stop. B. The object will continue to move to the right, slowing down but never coming to a complete stop. C. The object will slow down, momentarily stopping, then pick up speed moving to the left. D. The object cannot have a negative acceleration and be moving to the right.

C

Which of the following quantities has units of a velocity? (There could be more than one correct choice.) A. 9.8 m/s2 downward B. 40 km southwest C. 186,000 mi D. 9.8 m/s downward E. -120 m/s

D E

in which of the following cases does a car have a negative velocity and a positive acceleration? A car that is traveling in the

-x direction decreasing in speed.

Now assume that the insect, instead of floating on the surface, is resting on a leaf above the water surface at a horizontal distance 0.600 m away from the fish. The archerfish successfully shoots down the resting insect by spitting water drops at the same angle 60∘ above the surface and with the same initial speed vvv as before. At what height hhh above the surface was the insect?

.260 m

A nerve conduction velocity test (NCV) is an electrical test that is used to evaluate the function of nerves. A NCV on a patient's sciatic nerve (length of 0.80 m) reveals a conduction velocity of 20 m/s how long did it take the impulses to travel along the nerves

0.040 s

Suppose that a particular artillery piece has a range RRR = 7330 yards . Find its range in miles. Use the facts that 1mile=5280ft and 3ft=1yard

R = 4.16 miles

A ball is thrown straight up What are the velocity and acceleration of the ball at the highest point in its path?

V = 0 a = 9.8m/s2 down

Suppose that an object is moving with a constant velocity. Which statement concerning its acceleration must be correct? A. The acceleration is equal to zero. B. The acceleration is constantly decreasing. C. The acceleration is constantly increasing. D. The acceleration is a constant non-zero value.

a

A force of 35.0 N is required to start a 6.0-kg box moving across a horizontal concrete floor. a. What is the coefficient of static friction between the box and the floor? b. If the 35.0-N force continues, the box accelerates at 0.60 m/s2 . What is the coefficient of kinetic friction?

a. 0.60 b. 0.53

A 28.0-kg block is connected to an empty 2.86-kg bucket by a cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.49 and the coefficient of kinetic friction between the table and the block is 0.27. Sand is gradually added to the bucket until the system just begins to move. Ignore mass of cord. a. Calculate the mass of sand added to the bucket. b. Calculate the acceleration of the system.

a. 11 kg b. 1.4 m/s2

The block shown in (Figure 1) has mass mm = 7.0 kg and lies on a fixed smooth frictionless plane tilted at an angle θtheta = 21.5∘ to the horizontal. a. determine the acceleration of the block as it slides down the plane. b. if the block starts from rest 18.0 m up the plane from its base, what will be the block's speed when it reaches the bottom of the incline?

a. 3.59 m/s2 b. 11.4 m/s

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

average acceleration

Which statements are not not valid for a projectile? Take up as positive. a. The projectile has the same x velocity at any point on its path. b. The acceleration of the projectile is positive and decreasing when the projectile is moving upwards, zero at the top, and increasingly negative as the projectile descends. c. The acceleration of the projectile is a constant negative value. d. The y component of the velocity of the projectile is zero at the highest point of the projectile's path. e. The velocity at the highest point is zero.

b and e

Suppose that a car traveling to the west (-x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration must be correct? A. Its acceleration is decreasing in magnitude as the car slows down. B. Its acceleration is zero. C. Its acceleration is positive. D.Its acceleration is negative.

c

You are adding vectors of length 20 and 40 units. Which of the following choices is a possible resultant magnitude? A. 0 B. 18 C. 37 D. 64 E. 100

c

which of the following statements is true? At the highest point, a. the magnitude of the acceleration is zero. b. the magnitude of the velocity is zero. c. the magnitude of the velocity is the slowest. d. more than one of the above is true. e. none of the above are true.

c

Once you have selected a coordinate system, you can express a two-dimensional vector using a pair of quantities known collectively as __________.

components

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

d

Velocity differs from speed in that velocity indicates a particle's __________ of motion.

direction

Speed differs from velocity in the same way that __________ differs from displacement.

distance

A baseball player hits a ball that soars high into the air. After the ball has left the bat, and while it is traveling upward, what is the direction of acceleration Ignore air resistance.

down

If the acceleration of an object is zero, then that object cannot be moving. true or false

false

An object moving in the +x direction experiences an acceleration of +2.0 m/s2. This means the object

is increasing its velocity by 2 m/s every second

A car travels 10 m/s east. Another car travels 10 m/s north. The relative speed of the first car with respect to the second is

less than 20 m/s

A vector has, by definition, has both __________ and direction.

magnitude

To convert from ft^2 to yd^2 , you should

multiply by 1/9

The __________ of the particle at point A differ(s) as expressed in one coordinate system compared to the other, but the __________ from A to B is/are the same as expressed in both coordinate systems.

position displacement

Consider a car that travels between points A and B. The car's average speed can be greater than the magnitude of its average velocity, but the magnitude of its average velocity can never be greater than its average speed. True or False

true magnitude of velocity is <= average speed

What is the speed of a car going v=1.000mph in SI units? Notice that you will need to change from miles to meters and from hours to seconds. You can do each conversion separately. Use the facts that 1mile=1609m and 1hour=3600s

v = 0.4469 m/s

Unlike speed, velocity is a __________ quantity.

vector

vector quantity

velocity acceleration average velocity displacement position

scalar quantities

speed distance

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of v0 = 53 m/sm/s at an angle of 35.0∘ with the horizontal, as shown in the figure Determine the time taken by the projectile to hit point PP at ground level.

t = 8.85 s