# Physics!

74,480 results, page 82

1. ### physics

a roller coaster moves 85m horizonally, then travels 45m at an angle of 30 degrees above the horizontal. what is its displacement from its starting point?
2. ### physics

a pendulum clockis lag by 2 min during a whole 24 hours.what correction should be made in its length so that it keep the right time?
3. ### explian why please its physics

expliain y the very high specific heat capacity of water leads to formation of land and sea breezes???
4. ### Physics

i have a line graph with positions 1-10 in the positive direction. if a toy car rolls from +3m to +5m, which of the following statements is true? a. Xf=+3 m b. Xi=+3 m c. delta x=+3 m d. Vavg=3 m/s
5. ### physics: relativity

I think I can rearrange the Lorentz contraction equation, solving for v using: v=sqrt[1-(L/Lo)^2] x c^2 Would someone check my thinking please? Thanks
6. ### Physics

Determine the energy neded to put 5kg, initially at rest on Earth's surface, into geosynchronous orbit. I get 2.9*10^8 where did I gow wrong?
7. ### Physics

If two pith balls - one which is neutral and another which has a charge of -9.6 uC (micro-Coulombs) - are touched together, how many extra electrons will each ball have?
8. ### physics

The temperature of 7.10 mol of an ideal monatomic gas is raised 15.0 K in an adiabatic process. what is the change ÄK in the average kinetic energy per atom?
9. ### Physics

What is the potential difference required to accelerate a deuteron of mass 3.3x10^27kg and charges 1.6x10^-19C from rest to a speed of 5.0x10^6m/s?

You want to show that V^2 - Vo^2 = 2 a (X - Xo) first rewrite that as: (V-Vo)(V+Vo) = 2a (X-Xo) now your average velocity during the interval = (V+Vo)/2 so X = Xo + t(V+Vo)/2 but V = Vo + a t so t = (V-Vo)/a so X = Xo +(V-Vo)(V+Vo)/2a we are there. -------------------- but ...
11. ### physics

A ball is thrown upward from a platform 5.1 meters high with a speed of 13 m/s at an angle 45 degrees from the horizontal. what is the magnitude of its velocity when it hits the ground?
12. ### Physics B

A car slows down from 23 m/s to rest in a distance of 85m. What is its constant acceleration? I got -6.224, but a friend was telling me it's -3.11 and that I had to divide by 2. Why is that?
13. ### physics

Find the time it would have taken a horse to run: displacement: +1609 m average acceleration: +0.0105 m/s^2 initial velocity: +16.58 m/s
14. ### physics

an airplane has a takeoff speed of 80 meters per second which it reaches 35 seconds after starting from rest. What is the minimum length of the runway?
15. ### Physics

If a 20 kg object fell to the surgace of the Earth froma height of 30 m, what would its final velocity be? (work problem from the stanpoint of linear motion)
16. ### Physics

How do you calculate and compare the gravitational and electrical forces between an electron and a proton separated by 10 to the negative 10 m. Is the answer: m x a = (4p2r/t2)= 10 - 30 x 4 x1021= 4x10
17. ### physics

a person whos mass is 102 kg stands on a beam supported by two ropes , A and B, he is standing on one foot to help you solve this problem.

Determine the x and y components if a dog walks to the park that is 24m, 30 degrees northwest. Please help i don't know how to go about solving this problem
19. ### physics

A car weighing 9800 N travels at 30 m/s. What braking force (to the nearest whole number) brings it to rest in 100 m???? THNX BOBPURSLeY
20. ### Physics

A 17 kg child descends a slide 3.5 m high and reaches the bottom with a speed of 1.5 m/s. How much thermal energy due to friction was generated in this process?
21. ### physics

A shop sign weighing 230 N is supported by a uniform 115 N beam as shown in Fig. 9-54. Find the tension in the guy wire.
22. ### physics

Is this a trick question? In order to move a heavy object you must push against it with a larger force than it pushes on you. Is this true or false?
23. ### Physics

i spent so much time putting this equation together, but now I'm so confused solving for T 110 g x 4.816 J/g/C x (T-17)+31g x 0.385J/g/C x (T-300)=0 Can you help me
24. ### Physics

i spent so much time putting this equation together, but now I'm so confused solving for T 110 g x 4.816 J/g/C x (T-17)+31g x 0.385J/g/C x (T-300)=0 Can you help me
25. ### physics

At what projection angle will the range of a projectile equal to 6 times its maximum height? I know its easy but ive been absent and missed class!
26. ### Physics

A golf ball is struck with a five iron on level ground. It lands 85.0 m away 4.60 s later. What was the magnitude and direction of the initial velocity
27. ### Physics

What is the angular momentum of a 2.4 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1800 rpm? How much torque is required to stop it in 4.0 s?
28. ### Physics

a plastic duck floats half-immersedi n water in the bathtub. What fraction of its volume would be immersed in a liquid of relative density 2.0?
29. ### physics

An automobile tire is rated to last for 60,000 miles. To an order of magnitude, through how many revolutions will it turn? I don't know what circumference i should use for 1 rev
30. ### physics

A 2.8 kg rectangular air mattress is 2.00m long,0.500 m wide and 0.100m thick. What mass can it support in water before sinking?
31. ### Physics

An airplane lands and starts down the runway at a southwest velocity of 43 m/s. What constant acceleration allows it to come to a stop in 1.2 km?Answer is in ___ m/s2.
32. ### physics

How large must the coefficient of static friction be between the tires and the road if a car is to round a level curve of radius 95-m at a speed of 80 km/h.
33. ### physics

Find the velocity v and position r as functions of t for a particle of mass m which starts from rest at x=0 at time t=0 and subject to the following forces: F=Fo F=Fo +bti F=Fo coswt F=kt^2
34. ### physics

if a van de graaff generator is charged to 50,000 volts, how much energy does it take to add an additional electron to the charge on the shere?
35. ### College Physics

When I graphically find a vector sum and then analytically solve for the resultant, I am getting two completely different answers. Why might this be?
36. ### Physics

A sled is initially given a shove up a frictionless 24.0° incline. It reaches a maximum vertical height 1.10 m higher than where it started. What was its initial speed?
37. ### Physics

A sled is initially given a shove up a frictionless 24.0° incline. It reaches a maximum vertical height 1.10 m higher than where it started. What was its initial speed?
38. ### Physics

a hoop of radius .5 m & mass .2 kg is released from rest & rolls down an inclined plane. how fast is it moving when it has dropped a vertical distance of 3 m?
39. ### physics

A weight suspended from a spring is seen to bob up and down over a distance of 50 centimeters 2 times each second. What is its frequency? What is its period? What is its amplitude?
40. ### physics help

Assuming a typical efficiency for energy use by the body, how many slices of pizza must you eat to walk for 3.0 hr at a speed of 5.0 km/hr ? (Assume your mass is 68 kg).
41. ### Physics

The range of human hearing extends from approximately 20 Hz to 20000 Hz. Find the wavelength of these extremes when the speed of sound in air is equal to 343 m/s.
42. ### physics

A merry go round has a radius of 3.5 meters. How far does a child standing at the edge travel (path length) if the wheel is rotated 13.0 radians?
43. ### Physics

h_ttp:_//img215_.imageshack_.us/gal_.php?g=88875061_.jpg Anyone care to do....all the problems D:. Yes, I am desperate. (take away the underscores)
44. ### college physics

How fast (in rpm) must a centrifuge rotate if a particle 9.50 cm from the axis of rotation is to experience an acceleration of 113000 g's? Need help please.
45. ### physics

An electric iron has a resistance of ohms. How much heat energy is produced in 10 minutes if the current passing through the device is 10 amps?
46. ### Physics- Lenses

A planoconvex lens is to have a focal length of 28.5 cm. If made from fused quartz, what must be the radius of curvature of the convex surface?
47. ### College Physics

A 0.30-m-radius automobile tire rotates how many radians after starting from rest and accelerating at a constant 2.0 rad/s^2 over a 5.0-s interval?
48. ### physics

Van de Graaff generator is charged to 50,000 volts, how much energy does it take to add an additional electron to the charge on the sphere?
49. ### gen physics II

If a doubly-ionized oxygen atom (O–2) is accelerated from rest by going through a potential difference of 20 V, what will be the change in its kinetic energy?
50. ### physics

A pendulum has a mass of 3-kg, a length of 1.3 meter, and swings through a (half) arc of 30 degrees. To the tenth of a Joule, what is its maximum Kinetic Energy?
51. ### physics

A ball thrown straight up takes 5.80 seconds to go up and come back down to its starting point. Neglecting air resistance, how high (in m) does it go?
52. ### physics

to tighen a nut you exert 15N of force on wrench, which is a distance of 0.50m from pivot point. calculate amonut of torque produced...
53. ### Physics

I have a quick question, If a ballplayer catches a ball 3.0s after throwing it vertically upward. With what speed did he throw it, and what height did it reach?
54. ### College Physics II

Consider a region in space where a uniform electric field E = 7450 N/C points in the negative x direction. What is the distance between the +13.1 V and the +14.1 V equipotentials?
55. ### Physics

A hiker shouts towards a vertical cliff 465 m away. The echo is heard 2.75 s. later. The wavelength of the sound is 0.750 m. What is its frequency?
56. ### physics

total time for a rock drop from top of the well to the bottom and the sound bouve back is 5.6 sec, the well dept is 450 ft, true or false
57. ### Physics

What will be the equilibrium temperature when a 245 g block of copper at 285 oC is placed in a 145 g aluminum calorimeter cup containing 825 g of water at 12.0 oC?
58. ### physics

An old-fashioned single-play vinyl record rotates on a turntable at 46.0 rpm. What are (a) the angular velocity in rad/s and (b) the period of the motion?
59. ### physics

a block of ice initially sliding at 15m/s on a frozen pond comes to rest after traveling 90 meters. What is the coefficient of friction?
60. ### physics

What average force is needed to accelerate a 6.00-gram pellet from rest to 110 over a distance of 0.800 along the barrel of a rifle?
61. ### college physics

a block of ice initially sliding at 15m/s on a frozenpond comes to rest after traveling 90 meters. What is the coefficient friction?
62. ### physics

The coefficient of kinetic friction for a 25 -kg bobsled on a track is 0.10.What force is required to push it down a 6.0^\circ incline and achieve a speed of 67 km/h at the end of 75 {\rm m}?
63. ### physics

The roller-coaster car shown in Fig. 6-41 (h1 = 50 m, h2 = 11 m, h3 = 30 m), is dragged up to point 1 where it is released from rest. Assuming no friction, calculate the speed at points 2, 3, and 4
64. ### physics

How large must the coefficient of static friction be between the tires and the road if a car is to round a level curve of radius 89 at a speed of 93 ?
65. ### Physics

An old-fashioned single-play vinyl record rotates on a turntable at 40.0 rpm. What are (a) the angular velocity in rad/s and (b) the period of the motion?
66. ### Physics

If the force of friction is constant, prove that the stopping distance of a car on a level road varies directly with the square of the initial speed.
67. ### physics

A basketball is thrown at 45° to the horizontal. The hoop is located 4.5m away horizontally at a height of 1m above the point of release. What is the required initial speed?
68. ### Physics

Is it possible that dye does not really remove the yellow stains, although it makes the fabric end up looking whiter. explain how this maybe the case!!
69. ### Physics

What average force is needed to accelerate a 8.00-gram pellet from rest to 135 m/s over a distance of 0.800 m along the barrel of a rifle?
70. ### physics

A 50.0 kg gymast hangs vertically from a pair of parallel rings. If the ropes are supported so that they make an angle of 45 degrees with the ceiling, what is the tension in each rope?
71. ### physics

an elevator lifts 4 person each with an average mass of 72 kg to a height of of 20 metre in one minute calculate 1 the work done by the lift and 2 the power exerted
72. ### Physics

What equations should I use to calculate the effective value of g, the acceleration of gravity (in meters/second^2), at 5800 km above the earth's surface?
73. ### AP physics

suppose that the surface (radius=r) of the space station is rotating at 35.8 m/s. what must be the value of r for the astronauts to weigh one-half their earth weight?
74. ### AP Physics

a 45 kg object slides down an uneven frictionless incline from rest without rotating. What is its speed after it travels 2.5 meters vertically
75. ### Physics HELP!!!

In a classic model, the electron of a hydrogen atom circles the proton at a radius of 0.0529·10−9m when it is in the n=1 state. What is its electric potential energy?
76. ### Physics

A baseball is popped straight up into the air and has a hang-time of 6.25 s. Determine the height to which the ball rises before it reaches its peak.
77. ### physics

In a classic model, the electron of a hydrogen atom circles the proton at a radius of 0.052910−9m when it is in the n=1 state. What is its electric potential energy?
78. ### Physics

A circular off ramp has a radius of 74 m and a posted speed limit of 50km/h. If the road is horizontal, what is the minimum coefficient of friction needed?
79. ### Physics earth & Space

toward what direction, north or south would you look to the sun at noon on june 21-22 if you lived at the following latitudes
80. ### Physics

Calculate the force exerted on a rocket, given that the propelling gases are expelled at a rate of 1800 kg/s with a speed of 3.8×104 m/s (at the moment of takeoff).
81. ### College Physics

A child swings a yo-yo of weight mg in a horizontal circle so that the cord makes an angle of 30 degrees with the vertical. Find the centripetal acceleration.
82. ### physics

Frosty the Snowman was a jolly happy soul of mass 85 kg. If his initial temperature was -19C , how much heat did he absorb till he was at 25C ?
83. ### physics homework

0.2kg mass hangs at the end of the wire. what is the tension if the ball is then whirled around in a horizontal circle with tangential velocity of 5m/s
84. ### Physics

A 21.0 kg child descends a slide 3.4 m high and reaches the bottom with a speed of 2.0 m/s. How much thermal energy due to friction was generated in this process?
85. ### physics

As a young boy swings a yo-yo parallel to the ground and above his head, the yo-yo has a centripetal acceleration of 250m/s^2. If the yo-yo's string is 0.50 m long, what is the yo-yo's tangential speed?
86. ### Physics

Intravenous infusions are often made under gravity. At what height should the bottle be placed so the liquid pressure is 700 mm-H2O?
87. ### Physics

I have a spring on a horizontal frictionless surface. Initially it is un-stretched and at x = 0 cm. I then pull it back 10 cm and release it. What is the amplitude of the oscillations (the object has mass m)?
88. ### Physics

Calculate the vertical distance an object dropped from rest would cover in 12s if it fell freely without air resistance.
89. ### Physics

When tossed upward and hit horizontally by a batter, a 0.23 kg softball receives an impulse of 2.0 N·s. With what horizontal speed does the ball move away from the bat?
90. ### PHYSICS

What is the angular momentum of a 2.7 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1600 rpm? How much torque is required to stop it in 4.4 s?
91. ### physics

harry takes a space voyage and returns to find his twin sister has aged more than he has. This is evidence that they have been in different?
92. ### physics

is the momentum and force the same for a equal mass cars when: 1. they collide head on both at 30 m/s. 2.one collides with a brick wall at 60m/s
93. ### physics

Bob is riding his bike along at 2m/s and drops his 2kg backpack from a height of 1.5 meters. What is the backpacks resulting velocity when it strikes the ground?
94. ### physics

a man exerts 200 N force on a 18 kg lawnmower handle as he pushes it at constant velocity . the hantle makes an angle os 50 degrees with the ground.
95. ### physics

Sam tosses a ball horizontally off a footbridge at 3.2 m/s. How much time passes after he releases it until its speed doubles?
96. ### physics

Sam tosses a ball horizontally off a footbridge at 3.1 m/s. How much time passes after he releases it until its speed doubles?
97. ### physics

if a ball is thrown vertically upward and is caught 5 seconds,how fast must have been going when it left the person s hand?help
98. ### physics

a boy with a mass of 60kg climbs a 10m vertially up a ladder. A) how far did he travel? B) how much work is done? C) what are the energy changes here?
99. ### Physics

What is the maximum circular speed the astronaut can have before he breaks free of gravity and goes drifting off into space?
100. ### physics

A bar 5m long has a weight of 50nt attached to the other end is 80nt. Determine the magnitude, direction, and point of application of the equilibriant.