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  • Phsyics help!?

    1. A student of mass m = 73 kg runs at a velocity vi = 1.53 m/s before jumping on a skateboard. After jumping on the board the student has a velocity vf = 1.45 m/s. What is the mass of the skateboard, in kilograms? 

    2. A student of mass m1 = 63 kg runs towards his skateboard, which has a mass m2 = 2.8 kg and is d = 2.95 m ahead of him. He begins at rest and accelerates at a constant rate of a = 0.75 m/s2. When he reaches the skateboard he jumps on it. What is the velocity of the student and skateboard in meters per second? 

    3.  A crate of mass 54 kg containing bananas is sliding in a straight line on a frictionless surface at a constant velocity of 11 m/s. A monkey of mass 39 kg hanging from the ceiling times it correctly and jumps vertically down landing in the crate. At the time the monkey lands in the crate his velocity is 12 m/s vertically downward. What is the velocity, in meters per second, of the crate with monkey afterwards? 

    4.  A runaway train car that has a mass of 14000 kg travels at a speed of 5.4 m/s down a track.

    Randomized Variables

    m = 14000 kg

    v = 5.4 m/s

    F = 1600 N

    What is the time required for a force F to bring the car to rest, expressed in terms of m, v, and F? 

    5. Suppose that a garbage truck is 1.1 × 104 kg and is initially moving at 23.5 m/s. What is the speed of the garbage truck, in meters per second, just after it hits and adheres to a trash can that is 175 kg and initially at rest? 

    Physics2 months ago
  • Physics help?

     A bullet is accelerated down the barrel of a gun by hot gases produced in the combustion of gun powder.

    m = 0.0325 kg

    v = 595 m/s

    t = 2.2 ms

    What is the magnitude of the average force exerted on a bullet of mass m to accelerate it to a speed v in a time interval of t? 

    Physics2 months ago
  • Physics Help?

    1. A. A student standing on a cliff that is a vertical height d = 8.0 m above the level ground throws a stone with velocity v0 = 21 m/s at an angle θ = 21 ° below horizontal. The stone moves without air resistance; use a Cartesian coordinate system with the origin at the stone's initial position. With what speed, vf in meters per second, does the stone strike the ground? 

    1. B. If the stone had been thrown from the clifftop with the same initial speed and the same angle, but above the horizontal, would its impact velocity be different? 

    2. A. A student standing on a cliff that is a vertical height d = 25 ft above the level ground throws a stone with velocity v0 = 99 ft/s at an angle θ = 15 ° below horizontal. The stone moves without air resistance; use a Cartesian coordinate system with the origin at the stone's initial position. With what speed, vf in feet per second, does the stone strike the ground? 

    2. B. If the stone had been thrown from the clifftop with the same initial speed and the same angle, but above the horizontal, would its impact velocity be different? 

    Physics2 months ago
  • Physics Help!!!!?

    1. An object of mass 2.6 kg that is initially at rest is accelerated by a constant force.  After the force acts on the object over a distance of 2.1 m, the speed of the object is 5.5 m/s.  What is the magnitude of the force in newtons?  

    2. A block slides on a horizontal surface with an initial speed of 22 m/s.   If the block takes 4  s to come to a stop, what is the coefficient of kinetic friction, μk between the block and the surface?  Take g = 10 m/s2. 

    1 AnswerPhysics5 months ago
  • Physics Homework Help?

    3. A rock is thrown off a vertical cliff at an angle of 51.2o above horizontal. The cliff is 61.3 m high and the ground extends horizontally from the base. The initial speed of the rock is 24.9 m/s. Neglect air resistance. How far, in meters, has the rock moved horizontally at the moment it reaches its maximum height?   

    How long, in seconds, after being thrown does the rock hit the ground?   

    How far from the base of the cliff, in meters, is the landing point of the rock?   

    How high above the ground, in meters, is the rock 2.16 s before it hits the ground?   

    How far horizontally from the cliff, in meters, is the rock 2.16 s before it hits the ground? 

    5. The weight of an astronaut plus his space suit on the Moon is only 240 N. How much do they weigh on Earth, in newtons, assuming the acceleration due to gravity on the moon is 1.67 m/s2? What is the mass of the astronaut and his space suit on the Moon, in kilograms? What is the mass of the astronaut and his spacesuit on the Earth, in kilograms? 

    2 AnswersPhysics5 months ago
  • Physics Homework Help?

    1.  Artemis shoots an arrow at a target that is a horizontal distance d = 85 m away; the bull’s-eye of the target is at same height as the release height of the arrow. At what angle, in degrees above the horizontal, must the arrow be released to hit the bull’s-eye if the arrow's initial speed is 38 m/s?  

    2. Apollo 14 astronaut Alan B. Shepard Jr. used an improvised six-iron to strike two golf balls while on the Fra Mauro region of the moon’s surface, making what some consider the longest golf drive in history. Assume one of the golf balls was struck with initial velocity v0 = 27 m/s at an angle θ = 34° above the horizontal. The gravitational acceleration on the moon’s surface is approximately 1/6 that on the earth’s surface. Use a Cartesian coordinate system with the origin at the ball's initial position.What horizontal distance, R in meters, did this golf ball travel before returning to the lunar surface? What is the numeric value of the ratio, f, of the horizontal distance traveled on the moon to the horizontal distance the ball would travel on Earth’s surface under the same conditions? 

    Physics5 months ago
  • Physics Homework Help?

    A ball is thrown vertically upwards in the air with an initial speed of 10 m/s and from a point that is 4.8 m above the ground. How long does it take for the ball to hit the ground? Take g = 10 m/s2 and ignore air resistance. 

    2 AnswersPhysics6 months ago
  • Help with vectors for physics homework?

    2. Consider the two vectors,

    A = 16.5x + 35.5y

    B = 5.7x - 21y

    2. A) What is the magnitude of the vector A - B? 

    I already found the answer to this, 57.5, but can't figure out the rest

    2. B) What is the angle of the vector A - B, measured counterclockwise in degrees from the positive x-axis? 

    2. C) What is the magnitude of the vector 3A + B? 

    2. D) What is the angle of the vector 3A+B, measured counterclockwise in degrees from the positive x-axis? 

    2 AnswersPhysics6 months ago
  • Help with physics homework? ?

    1. A diver explores a shallow reef off the coast of Belize. She initially swims d1 = 82.9 m north, makes a turn to the east and continues for d2 = 177.8 m, then follows a big grouper (a kind of fish) for d3 = 84.1 m in the direction θ = 41.7° north of east. Finally, she swims d4 = 193.9 m south.

    1. A) What is the straight-line distance between her initial and final positions in m?  

    1. B) Suppose she wants to swim back to her initial position in a straight line. In what direction should she swim? Express your answer as an angle in degrees north of west.  

    2. Consider the two vectors,

    A = 16.5x + 35.5y

    B = 5.7x - 21y

    2. A) What is the magnitude of the vector A - B? 

    2. B) What is the angle of the vector A - B, measured counterclockwise in degrees from the positive x-axis? 

    2. C) What is the magnitude of the vector 3A + B? 

    2. D) What is the angle of the vector 3A+B, measured counterclockwise in degrees from the positive x-axis? 

    1 AnswerPhysics6 months ago
  • Can you help with my physics homework? ?

    1. A bicycle initially at rest accelerates for t = 16.5 seconds at a rate of a = 1.5 m/s2. 

    1. A)Calculate the distance in meters traveled by this bike.1. B)  Enter an expression, in terms of defined quantities, for the final velocity of the bicycle after time t. 1. C) Calculate the final speed, in meters per second. 2. Two cars both cover a straight distance, d = 257 m, in time t = 16 s. Car A moves at a constant velocity (vA). Car B moves at a constant acceleration (aB), starting from an initial velocity of v0B = 8.5 m/s. Assume both cars are moving in the positive x-direction.2. A) What is the velocity of car a?2. B) What is the final velocity of car b?2. C) What is the acceleration of car b?3. A bullet is shot straight up into the air from ground level. It reaches a maximum height at h = 713 m.3. A) Calculate initial speed of bullet in m/s3. B) Calculate the total flight time in seconds until the bullet reaches the ground 

    2 AnswersPhysics6 months ago
  • what pressure will 3.20 mol of nitrogen gas exert if confined in a 15 L container at 100 C?

    R=0.0821 L atm/mol K

    13 atm

    1.75 atm

    6.53 atm

    3.27 atm

    150 atm

    1 AnswerChemistry7 months ago
  • what is the concentration in molarity when 10 g of K3PO4 is dissolved in H2O to give 350 ml of solution?

    Molar mass of K3PO4=212.3 g/mol

    .121M

    .135M

    .0285M

    .0565M

    .607M

    1 AnswerChemistry7 months ago
  • Intro to Chem help?

    1. A fragment of the DNA molecule has the base sequence tgac. what is the complimentary sequence

    A. TGAC

    B. GTCA

    C. ACTG

    D. CAGT

    E. AGTC

    2. What is the composition of crude oil?

    A. Mostly saturated hydrocarbons having 5-12 carbons per molecule

    B. Mostly saturated hydrocarbons having 12-20 carbons per molecule

    C. Mostly aromatic hydrocarbons

    D. Mostly hydrocarbons, but the precise composition varies widely depending on location

    E. Mostly unsaturated hydrocarbons having 5-12 carbons per molecule

    3. Which of the following statements is true of a radioactive tracer

    I. Chemically, a radioactive tracer behaves like a nonradioactive isotope

    II. A radioactive tracer is a very small amount of radioactive isotope added to a chemical, biological, or physical system to study the system

    III. A radioactive tracer can be detected in exceedingly small amounts by measuring the radiations emitted

    A. II only

    B. I only

    C. II and III

    D. III only

    E. I, II, and III

    1 AnswerChemistry7 months ago
  • Can you help me with my intro to chemistry homework?

    There are a few questions I can t figure out and my professor hasn t responded to my emails.. I ve waited for 3 days and the homework is due tonight.

    1. Calculate the number of moles of O2 required to react with phosphorous to produce 3.56 g of P4O6 (Molar mass P4O6=219.9 g/mol)

    A. 0.097 mol

    B. 0.111 mol

    C. 0.0324 mol

    D. 0.0486 mol

    E. 0.0162 mol

    2. How many electrons does the ion 35 17 Cl- have?

    A. 16

    B. 19

    C. 34

    D. 36

    E. 18

    (I thought the answer to this would be 17, but that s not an option..)

    3. A sample of amonium phosphate contains .104 mol of nitrogen atoms. The number of moles in the oxygen sample is

    A. .41 mol

    B. .419 mol

    C. 4.6 mol

    D. .0104 mol

    E. .139 mol

    Any help is much appreciated!!! I was able to figure out the other 6 problems on this assignment, but I have no idea how to even approach these 3. Thank you!!!

    2 AnswersChemistry7 months ago
  • Why won’t my cat leave my desk?

    I took in my brothers cat in March of last year because he threw her out. She chose my desk as a place of comfort, and has stayed there since. She’s too anxious to go anywhere else. I have 4 other cats, they all coexist with her pretty well, but she’s nervous around them. She rarely leaves the desk, but when she does she’ll sit on the chair or come onto my bed. Sometimes I take her out into the living room and she’ll sit on the back of the couch for a while, but I don’t do that too often because I don’t want to stress her out and I don’t know if she’s comfortable with it. If I put her on my bed or on the floor, she goes right back to the desk. I thought if I gave her time, she’d see that she lives in a safe place now (she wasn’t treated well before) and she’d grow out of the desk thing but she hasn’t and I don’t know how to help her. 

    She has a box and a curved scratching board that she likes to lay in, and the desk is right in front of a window that she likes to look out of. I also make sure she always has toys. But I know she isn’t being mentally or physically stimulated and I feel really bad for her. How can I get her to be comfortable and confident enough to leave the desk? 

    Also, I know you’re wondering, I have a container with a snap on lid she uses as a litter box. I take the lid off 3-4 times a day so she has the opportunity to go, then put the lid back on so my room doesn’t smell like litter. 

    4 AnswersCats10 months ago
  • What s wrong with my car?

    It s loud when accelerating and doesn t seem to want to speed up. It was a struggle to get it up to 60, now it doesn t even want to reach 40

    In august I had the transmission replaced, not sure if that might be related

    8 AnswersMaintenance & Repairs1 year ago
  • Why can t I play videos on my laptop?

    No videos will play on YouTube, Facebook, Twitter, etc. I have Windows 10 and use Windows Edge. They won t play on FIrefox either. They play on Chrome, but there is no sound. I have Adobe. I updated my GPU driver. Sometimes when I update my laptop, videos will play, but they don t work again the next day.

    2 AnswersLaptops & Notebooks2 years ago
  • Why was I given the Hepatitis B vaccine at 17?

    I went to the doctor for a check up and she told me I needed the vaccine, and I didn't want it so I told her I'd wait. Next time I went, my mom was with me and she made me get it. Recently I found out that hepatitis B vaccines are given as a 3 part series in infants. Why would I be randomly given one vaccine at 17?

    The vaccine caused me a few health issues that I am still dealing with, and it is sort of irritating that I was given a vaccine only to later find out, I shouldn't have received it at all.

    3 AnswersInfectious Diseases3 years ago
  • Question about Jury Duty exemption?

    I obtained a note from my doctor for medical exemption from Jury Duty. I mailed the letter to the appropriate location at least 1 week ago, however no one has contacted me to verify they received it. It starts tomorrow, and no groups have been called yet, however I was in group 6, so my group will very likely be called first. I don't want to get in trouble for no showing even though I sent the letter in... Should they have sent me something saying they got it?

    2 AnswersCivic Participation3 years ago