PHY final

At what angle to the ground should you kick the ball for the maximum "hang time" - that is, the maximum time in the air? a) 30 degrees b) 45 degrees c) 60 degrees d) 90 degrees

Ch. 1,2,3 90 Degrees

For a projectile, which of the following quantities are constant during the flight: x, y, vx, vy, v, ax, ay? Circle all that apply. x y vx vy ax ay Which of the quantities are zero throughout the flight? Circle all that apply. x y vx vy ax ay

Ch. 1,2,3 Constant: vx ax ay Zero: ax

An ascending elevator, hanging from a cable, is coming to a stop. Identify all forces acting on the elevator from the list below. Select all that apply. o Kinetic friction o Weight o Normal force o Static friction o Tension

Ch. 4,5,6 -Weight -Tension

A 5000 kg truck is parked on a 7.0 degree slope. How big is the friction force on the truck? Express your answer with the appropriate units. Fs=

Ch 4,5,6 Fs= 5971.59 N

Home--------Sue------------------Cinema 2MI. 3MI shows Sue along the straight-line path between her home and the cinema. What is Sue's position x if her home is the origin? Assume the positive direction is to the right. Express your answer in miles. X= What is Sue's position x if the cinema is the origin? Assume the positive direction is to the right. Express your answer in miles. X=

Ch, 1,2,3 x= 2 miles x= -3 miles

It takes Harry 44 s to walk from x1 = -12 m to x2 = -42 m . What is his velocity? Express your answer in meters per second. V=

Ch. 1,2,3 V= -0.68 m/s

You are cycling around a circular track at a constant speed. Does the magnitude of your acceleration change? The direction? a) The magnitude of the acceleration changes. But the direction doesn't. b) The magnitude and direction of the acceleration change. c) The magnitude of the acceleration doesn't change. But the direction does. d) The magnitude and direction of the acceleration don't change.

Ch. 1,2,3 c) The magnitude of the acceleration doesn't change. But the direction does.

A car traveling at 31 m/s runs out of gas while traveling up a 9.0 degree slope. How far will it coast before starting to roll back down? Express your answer in meters. d=

Ch. 1,2,3 d= 313.6 m

A security guard walks at a steady pace, traveling 110 m in one trip around the perimeter of a building. It takes him 260 s to make this trip. What is his speed? V=

Ch. 1,2,3 110m/260s= 0.42m/s

If you kick a football, at what angle to the ground should you kick the ball for the maximum range - that is, the greatest distance down the field? a) 30 degrees b) 45 degrees c) 60 degrees d) 90 degrees

Ch. 1,2,3 45 Degrees

Anna is running to the right, as shown in (Figure 1). Balls 1 and 2 are thrown toward her by friends standing on the ground. According to Anna, both balls are approaching her at the same speed. According to her friends, do the balls have the same speed? a) No b) Yes According to Anna's friends, which ball was thrown with the faster speed? a) Ball 2 b) Ball 1

Ch. 1,2,3 According to her friends, do the balls have the same speed? - NO According to Anna's friends, which ball was thrown with the faster speed? - BALL 1

Alan leaves Los Angeles at 8:00 a.m. to drive to San Francisco, 400 mi away. He travels at a steady 50 mph. Beth leaves Los Angeles at 9:00 a.m. and drives a steady 60 mph Who gets to San Francisco first? Write the name below. How long does the first to arrive have to wait for the second? Express your answer in minutes. t =

Ch. 1,2,3 Beth t= 20 min

You begin sliding down a 15 degree ski slope. Ignoring friction and air resistance, how fast will you be moving after 10 s? Express your answer in meters per second. V=

Ch. 1,2,3 V= 25m/s

A car travels along a straight east-west road. A coordinate system is established on the road, with x increasing to the east. The car ends up 12 mi west of the origin, which is defined as the intersection with Mulberry Road. If the car's displacement was -23 mi, on what side of Mulberry Road did the car start? How far from the intersection was the car at the start? a) The car started 11 mi east of Mulberry Road. b) The car started 12 mi west of Mulberry Road. c) The car started 12 mi east of Mulberry Road. d) The car started 11 mi west of Mulberry Road.

Ch. 1,2,3 a) The car started 11 mi east of Mulberry Road. 12+ (-23) = -11 mi

a speed skater moving across frictionless ice at 8.9 m/s hits a 5.1 m wide patch of rough ice. She slows steadily, then continues on at 5.7m/s What is her acceleration on the rough ice? Express your answer in meters per second squared. a =

Ch. 1,2,3 a= -4.6 m/s^2

Formula One racers speed up much more quickly than normal passenger vehicles, and they also can stop in a much shorter distance. A Formula One racer traveling at 90 m/s can stop in a distance of 110 m. What is the magnitude of the car's acceleration as it slows during braking? Express your answer with the appropriate units. a=

Ch. 1,2,3 a= 37 m/s^2

Jack and Jill ran up the hill at 2.7 m/s. The horizontal component of Jill's velocity vector was 2.5 m/s. What was the angle of the hill? Express your answer in degrees. Θ = What was the vertical component of Jill's velocity? Express your answer with the appropriate units. vy=

Ch. 1,2,3 cosΘ = 2.5/2.7 Θ= cos^-1 (2.5/2.7) Θ= 22 Degrees 2.7 Sin(22) = 1.0 m/s vy= 1.0 m/s

A car travels to the left at a steady speed for a few seconds, then brakes for a stop sign. Select the correct motion diagram of the car for the entire motion described here. The dots are numbered in order, starting with zero.

Ch. 1,2,3 look at picture

Keira starts at position x = 27 m along a coordinate axis. She then undergoes a displacement of -43 m What is her final position? Express your answer in meters. X=

Ch. 1,2,3 x= -16m

A position vector with magnitude 25 m points to the right and up. Its x-component is 20 m. What is the value of its y-component? Y=

Ch. 1,2,3 y= 15m

The figure below is a somewhat simplified velocity graph for Olympic sprinter Carl Lewis starting a 100 m dash. Estimate his acceleration during each of the intervals A, B, and C

Ch. 1,2,3 look at picture

A skier is sliding down a 15 degree slope. Friction is not negligible. Identify the forces on the skier. Check all that apply. o Normal force n⃗ o Weight w⃗ o Tension T⃗ o Kinetic friction f⃗ k o Static friction f⃗ s o Thrust F⃗ thrust

Ch. 4,5,6 -Normal force n -Weight w -Kinetic friction

What is the tension in the rope of the figure? 60kg . . . . . . . . . 100kg T=

Ch. 4,5,6 T-mg=0 T-60 (9.8) =0 T-588= 0 T= 588N

You are driving on the highway, and you come to a steep downhill section. As you roll down the hill, you take your foot off the gas pedal. You can ignore friction, but you can't ignore air resistance. Identify all the forces acting on the car. Check all that apply. o Weight, w⃗ o Normal force, n⃗ o Kinetic friction force, f⃗ k o Tension, T⃗ o Drag, D⃗ o Thrust

Ch. 4,5,6 Weight Normal force Drag

A constant force is applied to an object, causing the object to accelerate at 9.0 m/s^2 . -What will the acceleration be if the force is doubled? -What will the acceleration be if the object's mass is doubled? -What will the acceleration be if the force and the object's mass are both doubled? -What will the acceleration be if the force is doubled and the object's mass is halved?

Ch. 4,5,6 force is doubled? a= 18 m/s^2 object's mass is doubled? a= 4.5 m/s^2 if the force and the object's mass are both doubled? a= 9.0 m/s^2 What will the acceleration be if the force is doubled and the object's mass is halved? a= 36.0 m/s^2

A box is being dragged across the floor at a constant speed by a rope pulling horizontally on it. Friction is not negligible. Identify all the forces acting on the box. Check all that apply. o Normal force, n⃗ o Thrust, F⃗ thrust o Tension, T⃗ o Kinetic friction force, f⃗ k o Weight, w⃗

Ch. 4,5,6 -Normal force -Tension, T -Kinetic friction force -Weight

A 1300 kg car drives around a flat 230-mm-diameter circular track at 21 m/s. What is the magnitude of the net force on the car?

Ch. 4,5,6 5000 N

A 55 kg ice skater is gliding along at 3.5 m/s. Five seconds later her speed has dropped to 2.7m/s What is the magnitude of the kinetic friction acting on her skates? Express your answer with the appropriate units. F =

Ch. 4,5,6 F= 9N

The horse on a carousel is 4.2 m from the central axis. If the carousel rotates at 0.10 rev, how long does it take the horse to go around twice? t= How fast is a child on the horse going (in m/s)? v=

Ch. 4,5,6 If the carousel rotates at 0.10 rev, how long does it take the horse to go around twice? t= 20 s How fast is a child on the horse going (in m/s)? v= 2.6 s

An early submersible craft for deep-sea exploration was raised and lowered by a cable from a ship. When the craft was stationary, the tension in the cable was 7500 N. When the craft was lowered or raised at a steady rate, the motion through the water added an 1800 N drag force. What was the tension in the cable when the craft was being lowered to the seafloor? T= What was the tension in the cable when the craft was being raised from the seafloor? T=

Ch. 4,5,6 What was the tension in the cable when the craft was being lowered to the seafloor? T= 5700 N What was the tension in the cable when the craft was being raised from the seafloor? T= 9300N

A 2000 kg truck has put its front bumper against the rear bumper of a 2400 kg SUV to give it a push. With the engine at full power and good tires on good pavement, the maximum forward force on the truck is 18,000 N What is the maximum possible acceleration the truck can give the SUV? a= At this acceleration, what is the force of the SUV's bumper on the truck's bumper? FSUVon truck =

Ch. 4,5,6 a= 4.1 m/s^2 FSUVon truck = 9800N

A horizontal rope is tied to a 70 kg box on frictionless ice. What is the tension in the rope if the box is at rest? T = What is the tension in the rope if the box moves at a steady 9.0 m/s? T = What is the tension in the rope if the box has vx = 9.0 m/s and ax = 5.0 m/s2 T =

Ch. 4,5,6 box is at rest? T= 0 N box moves at a steady 9.0 m/s? T= 0N box has vx = 9.0 m/s and ax = 5.0 m/s2 T= 350 N

One kind of baseball pitching machine works by rotating a light and stiff rigid rod about a horizontal axis until the ball is moving toward the target. Suppose a 144 g baseball is held 87 cm from the axis of rotation and released at the major league pitching speed of 87 mph. -What is the ball's centripetal acceleration just before it is released? -What is the magnitude of the net force that is acting on the ball just before it is released?

Ch. 4,5,6 centripetal acceleration= 17.0 x 10^2 m/s^2 magnitude of the net force= 25.0 x 10^1 N

In uniform circular motion, which of the following quantities are constant? Check all that apply. o the magnitude of the net force o instantaneous velocity o centripetal acceleration o speed

Ch. 4,5,6 the magnitude of the net force centripetal acceleration speed

Two workers are sliding 370 kg crate across the floor. One worker pushes forward on the crate with a force of 390 N while the other pulls in the same direction with a force of 320 N using a rope connected to the crate. Both forces are horizontal, and the crate slides with a constant speed. What is the crate's coefficient of kinetic friction on the floor? μk =

Ch. 4,5,6 μk = 0.1958