Physics final

A speed skater moving across frictionless ice at 8.7 m/sm/s hits a 6.0 mm -wide patch of rough ice. She slows steadily, then continues on at 5.9 m/sm/s .What is her acceleration on the rough ice?

-3.4 m/s

If a boat and its riders have a mass of 900 kg and the boat drifts in at 1.3 m/s how much work does Sam do to stop it?

-760 J

Chip begins rolling down a hill for the fun of it. He starts at the top of the hill with a speed of 0.1m/s and at the bottom of the hill has a speed of 2m/s. If the surface of the hill that Chip rolls along is 12 meters long and Chip rolls with a constant acceleration then what was Chip's acceleration on the hill. (Assume Chip travels in a straight line along the hill he is rolling in the positive x-direction.)

0.17m/s x^

A small, 300 g cart is moving at 1.60 m/s on a frictionless track when it collides with a larger, 2.00 kg cart at rest. After the collision, the small cart recoils at 0.820 m/s .What is the speed of the large cart after the collision?

0.36 m/s

A 20 g ball of clay traveling east at 2.0m/s collides with a 30 g ball of clay traveling 30∘∘ south of west at 1.0m/s.

0.41 m/s

How far must you stretch a spring with k = 1600 N/m to store 210 J of energy?

0.51 m

How far must you stretch a spring with k = 1300 N/m to store 200 J of energy?

0.55 m

If the car needs to be moving at 3.7 m/s for this to work, how high a hill do you need? (You can ignore friction and drag.)

0.70 m

A cyclist is rounding a 19-m-radius curve at 12 m/s . a)What is the minimum possible coefficient of static friction between the bike tires and the ground?

0.77

You throw a ball straight up for Orion from a height of 1.3 meters. You released the ball with a speed of 4.0m/s. If Orion catches the ball at a height of 0.50 meters, at what time after you release the ball does he grab the ball?

0.98s

A 2.1 kg block slides along a frictionless surface at 1.0 m/s . A second block, sliding at a faster 4.4 m/s , collides with the first from behind and sticks to it. The final velocity of the combined blocks is 2.3 m/s . a) What was the mass of the second block?

1.3 kg

Two tugboats pull a disabled supertanker. Each tug exerts a constant force of 1.20×106 N , one at an angle 14.0 ∘∘ west of north, and the other at an angle 14.0 ∘∘ east of north, as they pull the tanker a distance 0.720 km toward the north.

1.68×109J

What is the angular speed of the tip of the minute hand on a clock, in rad/s?

1.75 * 10^3 rads/ s

Suppose the moon were held in its orbit not by gravity but by a massless cable attached to the center of the earth. What would be the tension in the cable?

1.99 *10^20 N

A 30 kg child slides down a playground slide at a constant speed. The slide has a height of 3.0 m and is 7.2 m long. Using energy considerations, find the magnitude of the kinetic friction force acting on the child.

120 N

A hockey puck is given an initial speed of 4.2 m/s Part complete If the coefficient of kinetic friction between the puck and the ice is 0.05, how far does the puck slide before coming to rest? Solve this problem using conservation of energy.

18 m

A child on a swing set swings back and forth with a period of 3.0 s and an amplitude of 25∘∘. Suppose that the motion is simple harmonic. a) What is the maximum speed of the child as she swings?

2 m/s

A 480 g peregrine falcon reaches a speed of 63 m/s in a vertical dive called a stoop. a)If we assume that the falcon speeds up under the influence of gravity only, what is the minimum height of the dive needed to achieve this speed?

200 m

Two strings are adjusted to vibrate at exactly 200 Hz . Then the tension in one string is increased slightly. Afterward, three beats per second are heard when the strings vibrate at the same time. What is the new frequency of the string that was tightened?

203 Hz

At what speed do a bicycle and its rider, with a combined mass of 100 kg, have the same momentum as a 1300 kg car traveling at 1.8 m/s ?

23 m/s

The longest recorded pass in an NFL game traveled 81 yards in the air from the quarterback to the receiver.Assuming that the pass was thrown at the optimal 45 ∘∘ angle, what was the speed at which the ball left the quarterback's hand?

27 m/s

Squid rely on jet propulsion when a rapid escape is necessary. A 1.5 kg squid at rest pulls 0.10 kg of water into its mantle, then ejects this water at a remarkable 45 m/s

3.0 m/s

Two strings are adjusted to vibrate at exactly 300 Hz . Then the tension in one string is increased slightly. Afterward, three beats per second are heard when the strings vibrate at the same time. a) What is the new frequency of the string that was tightened?

303 Hz

An astronaut's weight on earth is 800 N. What is his weight on Mars, where g=3.76m/s2?

310 N

Part complete How fast would a(n) 72 kg man need to run in order to have the same kinetic energy as an 8.0 g bullet fired at 390 m/s ?

4.1 m/s

A sinusoidal wave travels with speed 210 m/s . Its wavelength is 5.0 m .

42 Hz

A 1.04 kg block is attached to a horizontal spring with spring constant 3800 N/m . The block is at rest on a frictionless surface. A 11.8 g bullet is fired into the block, in the face opposite the spring, and sticks. a)What was the bullet's speed if the subsequent oscillations have an amplitude of 8.60 cm ?

461 m/s

A 300 g bird flying along at 6.2 m/s sees a 10 g insect heading straight toward it with a speed of 31 m/s (as measured by an observer on the ground, not by the bird). The bird opens its mouth wide and enjoys a nice lunch.What is the bird's speed immediately after swallowing?

5 m/s

Excellent human jumpers can leap straight up to a height of 130 cmcm off the ground. a)To reach this height, with what speed would a person need to leave the ground?

5 m/s

A 5000 kg open train car is rolling on frictionless rails at 22.0m/s when it starts pouring rain. A few minutes later, the car's speed is 20.0m/s a) What mass of water has collected in the car?

500 kg

Ellawyn is running a 5km run for PE. She manages to keep a steady constant velocity of 2 m/s along the straight road for 4km of the run. For the last 1km, she runs with a negative acceleration of 0.0005m/s2. How long does it take for Ellawyn to complete her run?

540s

You are driving down the highway late one night at 20 m/sm/s when a deer steps onto the road 35 mm in front of you. Your reaction time before stepping on the brakes is 0.50 ss , and the maximum deceleration of your car is 10 m/s2m/s2 . How much distance is between you and the deer when you come to a stop?

5m

What minimum speed does a 160 g puck need to make it to the top of a 5.0 m -long, 22 ∘∘ frictionless ramp?

6.1 m/s

A 30 g ball of clay traveling east at 4.5 m/s collides and sticks together with a 60 g ball of clay traveling north at 9.0 m/s . a) What is the speed of the resulting ball of clay?

6.2 m/s

Buttercup slides to a stop after slipping when running in a straight line with a velocity of 2m/s in the positive x-direction. How long does she slip if her acceleration is -0.3m/s2?

6.7 m/s

A 5000 kg truck is parked on a 7.0∘∘ slope. How big is the friction force on the truck?

6000 N = fs

A man standing on very slick ice fires a rifle horizontally. The mass of the man together with the rifle is 70 kg , and the mass of the bullet is 10 g . a) If the bullet leaves the muzzle at a speed of 500 m/s , what is the final speed of the man?

7.1×10^−2 m/s

A 77 kg bike racer climbs a 1300-m-long section of road that has a slope of 4.3 ∘∘ . a)By how much does his gravitational potential energy change during this climb?

7.4 *10^4 J

A roller coaster car is going over the top of a 16-mm-radius circular rise. At the top of the hill, the passengers "feel light," with an apparent weight only 60 %% of their true weight. a)

7.9 m/s

A curve at a racetrack has a radius of 700 m and is banked at an angle of 7.0∘∘. On a rainy day, the coefficient of friction between the cars' tires and the track is 0.60. a) What is the maximum speed at which a car could go around this curve without slipping?

73 m/s

When you sneeze, the air in your lungs accelerates from rest to approximately 160 km/hr in about 0.55 seconds . What is the acceleration of the air in m/s2?

81 m/s^2

A 60 kg runner in a sprint moves at 11 m/sm/s. A 60 kg cheetah in a sprint moves at 33 m/s. a) By what factor does the kinetic energy of the cheetah exceed that of the human runner?

9

Suppose the free-fall acceleration at some location on earth was exactly 9.8000 m/s2. a)Part complete What would it be at the top of a 1200 mm -tall tower at this location?

9.79 m/s^2

An air-track glider is attached to a spring. The glider is pulled to the right and released from rest at t = 0 s. It then oscillates with a period of 2.0 s and a maximum speed of 58 cm/s . a) What is the amplitude of the oscillation?

A = 18 cm

Suppose E =2A + 3B where vector A→ has components Ax= 5, Ay = 2 and vector B→ has components Bx= -3, By = -5. What is the x-component of vector E→?

Ex= 1 Ey=11

A student throws a 110 g snowball at 8.5 m/s at the side of the schoolhouse, where it hits and sticks.

F =4.9 N

The free-fall acceleration on the moon is 1.62 m/s2 . What is the length of a pendulum whose period on the moon matches the period of a 1.90-m-long pendulum on the earth?

Lmoon =0.31m

An air-track glider attached to a spring oscillates between the 11.0 cmcm mark and the 65.0 cm mark on the track. The glider completes 15.0 oscillations in 37.0 s . What are the (a) period, (b) frequency, (c) amplitude, and (d) maximum speed of the glider?

T= 2.5s f= 0.41 hz A=27 cm vmax = 69 cm

Determine the tension in the rope at the point indicated with a dot. All objects are at rest. The strings and pulleys are massless, and the pulleys are frictionless m =5

T= 49 N

A 20 gg ball of clay traveling east at 2.0m/s collides with a 30 g ball of clay traveling 30∘∘ south of west at 1.0m/s. a) What is the speed of the resulting 50 g blob of clay? b) What is the direction of the resulting 50 g blob of clay?

a) 0.41 m/s b)47 s of e

A canoe has a velocity of 0.380 m/sm/s southeast relative to the earth. The canoe is on a river that is flowing at 0.720 m/sm/s east relative to the earth. a)Find the magnitude of the velocity VCR of the canoe relative to the river. b)Find the direction of the velocity of the canoe relative to the river.

a) 0.525 m/s b) 30.8 degrees s of w

A wind turbine has 12,000 kg blades that are 37 mm long. The blades spin at 21 rpm . a) If we model a blade as a point mass at the midpoint of the blade, what is the inward force necessary to provide each blade's centripetal acceleration?

a) 1.1×10^6

A large raindrop--the type that lands with a definite splat--has a mass of 0.014 g and hits your roof at a speed of 8.1 m/s a)What is the magnitude of the impulse delivered to your roof? b)If the raindrop comes to rest in 0.37 ms, what is the magnitude of the average force of the impact?

a) 1.1×10^−4 kg⋅m/s b) Fav =0.31 N

It takes a time of 2.70 s for the boat to travel from its highest point to its lowest, a total distance of 0.700 m . The fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart. a) How fast are the waves traveling? b) What is the amplitude A of each wave?

a) 1.20 m/s b) 0.350 m

Your forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can only withstand about 1.3 kN. a)If a 140 g baseball strikes your head at 29 m/s and stops in 0.0016 s , what is the magnitude of the ball's deceleration? b) What is the magnitude of the force that stops the baseball? c)What force does the baseball apply to your head?

a) 1.8*10^4 m/s^2 b) 2500N c)2500 N

A sinusoidal wave has period 0.15 s and wavelength 2.0 m . a) What is the wave speed?

a) 13 m/s

The airplane flies horizontally with constant speed of 422 km/hour at an altitude of 875 mm . The positive x and y directions are defined in the figure. For all parts, assume that the "island" refers to the point at a distance DDD from the point at which the package is released, as shown in the figure. Ignore the height of this point above sea level. Assume that the free-fall acceleration is g = 9.80 m/s2m/s2 . a)After a package is dropped from the plane, how long will it take for it to reach sea level from the time it is dropped? Assume that the package, like the plane, has an initial velocity of 422 km/hour in the horizontal direction. b)If the package is to land right on the island, at what horizontal distance D from the plane to the island should the package be released? c) What is the speed vf of the package when it hits the ground? d) The speed at which the package hits the ground is really fast! If a package hits the ground at such a speed, it can be crushed and also cause some serious damage on the ground. Which of the following would help decrease the speed with which the package hits the ground?

a) 13.4 s b)1570 m c)176 m/s d) decrease the plane's speed and height

A light-rail train going from one station to the next on a straight section of track accelerates from rest at 1.1 m/s2m/s2 for 20 ss. It then proceeds at constant speed for 1100 mm before slowing down at 2.2 m/s2m/s2 until it stops at the station. a) What is the distance between the stations? b)How much time does it take the train to go between the stations?

a) 1400 m b) 80 s

The displacement of a wave traveling in the positive x-direction is y(x,t)=(3.5cm)cos(2.7x−92t), where xx is in mm and t is in s. a) what is the frequency if this wave? b) What is the wavelength of this wave? c) What is the speed of this wave?

a) 15 hz b) 2.3 m c) 35 m/s

Anita is running to the right at 5 m/s , as shown in the figure. Balls 1 and 2 are thrown toward her by friends standing on the ground. According to Anita, both balls are approaching her at 10 m/s a)According to her friends, with what speed was ball 1 thrown? b) According to her friends, with what speed was ball 2 thrown?

a) 15 m/s b) 5 m/s

In the Olympic shot-put event, an athlete throws the shot with an initial speed of 12.0 m/s at a 40.0 ∘ angle from the horizontal. The shot leaves her hand at a height of 1.80 mm above the ground. a) How far does the shot travel? b) Repeat the calculation of the first part for angle 42.5 ∘ c) Repeat the calculation of the first part for angle 45 ∘ d) Repeat the calculation of the first part for angle 47.5 ∘∘ . e) At what angle of release does she throw the farthest?

a) 16.36 m b) 16.39 m c)16.31 m d) 16.13 e)42.5

A firecracker in a coconut blows the coconut into three pieces. Two pieces of equal mass fly off south and west, perpendicular to each other, at 25 m/s . The third piece has twice the mass as the other two. a) What is the speed of the third piece? b) What is the direction of the third piece?

a) 18 m/s b) 45 n of e

A mass on a string of unknown length oscillates as a pendulum with a period of 2.0 ss . Parts a to d are independent questions, each referring to the initial situation. What is the period if a) the mass is doubled b) the string L is doubled c) the sting L is halved d) the amplitude is doubled

a) 2 s b) 2.83 s c) 1.41 s d) 2 s

In this problem, you will apply kinematic equations to a jumping flea. Take the magnitude of free-fall acceleration to be 9.80 m/s2m/s2 . Ignore air resistance. a)A flea jumps straight up to a maximum height of 0.430 mm . What is its initial velocity v0as it leaves the ground? b)How long is the flea in the air from the time it jumps to the time it hits the ground?

a) 2.9 m/s b)0.592 s

The famous cliff divers of Acapulco leap from a perch 35 mm above the ocean.How fast are they moving when they reach the water surface? b) What happens to their kinetic energy as they slow to a stop in the water?

a) 26 m/s b) It is transformed into thermal energy of the diver and thermal and kinetic energy of surrounding water.

a) 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 mm 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. b) 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 v as before. At what height h above the surface was the insect?

a) 3.01 m/s b)0.260 m

A kid at the junior high cafeteria wants to propel an empty milk carton along a lunch table by hitting it with a 3.0 g spit ball. a) If he wants the speed of the 30 gg carton just after the spit ball hits it to be 0.30 m/s , at what speed should his 3.0 g spit ball hit the carton?

a) 3.3 m/s

A cannonball is fired horizontally from the top of a cliff. The cannon is at height H = 60.0 mm 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 a)Assume that the cannon is fired at time t=0tand that the cannonball hits the ground at time tg. What is the y position of the cannonball at the time tg/2? b)Given that the projectile lands at a distance D = 120 m from the cliff, as shown in the figure, find the initial speed of the projectile, v0. c) What is the y position of the cannonball when it is at distance D/2from the hill?

a) 45 m b)34.3 m/s c) 45m

Two physics students are doing a side competition during a game of bowling, seeing who can toss a ball with the larger momentum. The first bowler throws a 4.5 kg ball at 7.2 m/s a) A second bowler throws a 6.4 kg ball. What speed must she beat to win the competition?

a) 5.1 m/s

The 1.5 mm long hollow tube in the crest had connections to the nose and throat, a) If you model the tube as an open-closed system, what are the first three resonant frequencies? (Use 350 m/s for the speed of sound.)

a) 58,180,290 Hz

Olaf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400 kg that is traveling horizontally at 11.0 m/s . Olaf's mass is 70.3 kg a) If Olaf catches the ball, with what speed vf do Olaf and the ball move afterward? b) If the ball hits Olaf and bounces off his chest horizontally at 8.00 m/s in the opposite direction, what is his speed vf after the collision?

a) 6.22×10^−2 m/s b) vf=0.108m/s

The earth's radius is about 4000 miles. Kampala, the capital of Uganda, and Singapore are both nearly on the equator. The distance between them is 5000 miles. a) Through what angle do you turn, relative to the earth, if you fly from Kampala to Singapore? b)The flight from Kampala to Singapore takes 9 hours. What is the plane's angular speed?

a) 71.6 degrees b)3.86 * 10^-5 rad/s

The space shuttle is in a 220-mile-high orbit. a) What is the shuttle's orbital speed? b) What is the shuttle's orbital period?

a) 7700 m/s b) 91 minutes

The lowest frequency in the audible range is 20 Hz a) What is the length of the shortest open-open tube needed to produce this frequency? b) What is the length of the shortest open-closed tube needed to produce this frequency?

a) 8.6 m b) 4.3 m

World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s^2 How much horizontal force F must a sprinter of mass 56 kg exert on the starting blocks to produce this acceleration? b) Which body exerts the force that propels the sprinter, the blocks or the sprinter?

a) 840 N b) the blocks

A 200 g mass attached to a horizontal spring oscillates at a frequency of 2.0 Hz . At one instant, the mass is at x=5.0cm and has vx=−30cm/s a) Determine the period. b) Determine the amplitude. c) Determine the maximum speed. d) Determine the total energy.

a) T =0.50s b) A = 5.5 cm c) 70 cm/s d) 4.9×10^−2 J

A horizontal rope is tied to a 90 kg box on frictionless ice. a)What is the tension in the rope if the box is at rest? b) What is the tension in the rope if the box moves at a steady 8.0 m/s? c) Part complete What is the tension in the rope if the box has vx= 8.0 m/sand ax= 5.0 m/s2

a) T= 0 N b)T= 0 N c) T= 450 N

A 1.2 kg book is lying on a 0.70 m -high table. You pick it up and place it on a bookshelf 2.2 m above the floor. a) How much work does gravity do on the book? b)How much work does your hand do on the book?

a) W1 = -18J b) 18 J

A friend of yours is loudly singing a single note at 420 Hz while racing toward you at 24.3 m/s on a day when the speed of sound is 344 m/s . a)What frequency do you hear? b) What frequency does your friend hear if you suddenly start singing at 420 Hz?

a) f =452Hz b) f=450Hz

A 72 kg man weighs himself at the north pole and at the equator. a)what scale reading is higher? b)by how much?

a) north pole b) 2.4 N

a) What are the three longest wavelengths for standing waves on a 300-cm-long string that is fixed at both ends? b)If the frequency of the second-longest wavelength in part a is 55.0 Hz , what is the frequency of the third-longest wavelength?

a) λ =6.00,3.00,2.00m b) 82.5 hz

A ball with a horizontal speed of 1.25 m/s rolls off a bench 1.00 mm above the floor. a)How long will it take the ball to hit the floor? b) How far from a point on the floor directly below the edge of the bench will the ball land?

a)0.452 s b) 0.565 m

Two spheres are launched horizontally from a 1.2 m -high table. Sphere A is launched with an initial speed of 5.0 m/s . Sphere B is launched with an initial speed of 3.0 m/s a)What is the time for the sphere A to hit the floor? b)What is the time for the sphere B to hit the floor?

a)0.49s b)0.49s

A gray kangaroo can bound across a flat stretch of ground with each jump carrying it 11.0 mm from the takeoff point. a)Part complete If the kangaroo leaves the ground at a 22.0 ∘∘ angle, what is its takeoff speed ? b)What is its horizontal speed?

a)12.5 m/s b) 11.6 m/s

a) What constant acceleration, in SI units, must a car have to go from zero to 60 mph in 10 s ? b)What fraction of g is this? c)How far has the car traveled when it reaches 60 mph? Give your answer in SI units.

a)2.7 m/s^2 b)0.27g c)130 m

a)A plane accelerates from rest at a constant rate of 5.00 m/s2along a runway that is 1800 m long. Assume that the plane reaches the required takeoff velocity at the end of the runway. What is the time tTO needed to take off? b)What is the speed vTO of the plane as it takes off? c) What is the distance dfirst traveled by the plane in the first second of its run? d)What is the distance dlast traveled by the plane in the last second before taking off? e)What percentage of the takeoff velocity did the plane gain when it reached the midpoint of the runway?

a)26.8 s b)134 m/s c)2.50 m d)132 m e)71 %

a) When the displacement of a mass on a spring is 12 A the half of the amplitude, what fraction of the mechanical energy is kinetic energy? b) At what displacement, as a fraction of A, is the mechanical energy half kinetic and half potential?

a)75 % b) .707A

a) How much work does an elevator motor do to lift a 1000 kg elevator a height of 100 m? b)How much power must the motor supply to do this in 50 s at constant speed?

a)9.8 *10^ 5 J b)2.0 * 10^ 4 W

The angle of a pendulum is given byθ(t)=( 0.12 rad )cos⁡( 5.0 t) ,where t is in seconds. a) Determine the amplitude. b) Determine the frequency. c) Determine the length of the string. d) Determine the angle at 5.0 s

a)A =0.12 rad b) 0.80 Hz c)0.39 m d) 0.12 rad

A ball thrown horizontally with speed vi = 30.0 m/s travels a horizontal distance of d = 57.0 m before hitting the ground. From what height h was the ball thrown? a)When setting up projectile motion questions, which of the following characteristics of projectile motion are important to keep in mind? b)A ball thrown horizontally at vi= 30.0 m/s travels a horizontal distance of d = 57.0 mm before hitting the ground. From what height h was the ball thrown? c)If it takes a ball dropped from rest 1.900 s to fall to the ground, from what height H was it released?

a)Although the horizontal and vertical motions of a projectile are independent, they are connected through the time ΔtΔtDeltat that the object is in the air.Projectile motion is made up of two independent motions: uniform motion at constant velocity in the horizontal direction and free-fall motion in the vertical direction. b)17.7 m c)17.7 m

A whistle you use to call your hunting dog has a frequency of 21 kHz, but your dog is ignoring it. You suspect the whistle may not be working, but you can't hear sounds above 20 kHz To test it, you ask a friend to blow the whistle, then you hop on your bicycle. a) In which direction should you ride (toward or away from your friend) to know if the whistle is working? b) At what minimum speed should you ride to know if the whistle is working?

a)away from your friend b)16 m/s

An opera singer in a convertible sings a note at 600 Hz while cruising down the highway at 89 km/h . The speed of sound n the air is 343 m/s. a) What is the frequency heard by a person standing beside the road in front of the car? b) What is the frequency heard by a person standing beside the road behind the car?

a)f+ =650 Hz b)f−f− =560Hz

It takes the elevator in a skyscraper 4.0 s to reach its cruising speed of 10 m/s . A 60 kgpassenger gets aboard on the ground floor. a)What is the passenger's apparent weight before the elevator starts moving? b)What is the passenger's apparent weight while the elevator is speeding up? c)What is the passenger's apparent weight after the elevator reaches its cruising speed?

a)wapp =590 N b)740 N c)590 N

). As the carousel turns, the riders move in a large circle with the chains tilted out from the vertical. In one such carousel, the riders move in a 19.5-m-radius circle and take 8.5 s to complete one revolution. a) What is the angle of the chains, as measured from the vertical?

theta = 47 degrees