# Math/Physics

214,834 results, page 91

1. ### 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
2. ### 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?
3. ### 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?
4. ### 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?
5. ### 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?
6. ### 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?
7. ### 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}?
8. ### 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
9. ### 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 ?
10. ### 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?
11. ### 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.
12. ### 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?
13. ### 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!!
14. ### 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?
15. ### 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?
16. ### 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
17. ### 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?
18. ### 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?
19. ### 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
20. ### 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?
21. ### 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.
22. ### 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?
23. ### 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?
24. ### 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
25. ### 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).
26. ### 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.
27. ### 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 ?
28. ### 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
29. ### 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?
30. ### 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?
31. ### Physics

Intravenous infusions are often made under gravity. At what height should the bottle be placed so the liquid pressure is 700 mm-H2O?
32. ### 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)?
33. ### Physics

Calculate the vertical distance an object dropped from rest would cover in 12s if it fell freely without air resistance.
34. ### 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?
35. ### 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?
36. ### 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?
37. ### 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
38. ### 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?
39. ### 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.
40. ### 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?
41. ### 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?
42. ### 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
43. ### 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?
44. ### Physics

What is the maximum circular speed the astronaut can have before he breaks free of gravity and goes drifting off into space?
45. ### 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.
46. ### physics

How long does it take a plane, traveling at a constant speed of 160 m/s, to fly once around a circle whose radius is 3450 m?
47. ### physics

Explain the effect increasing temperature has on the following situations and what is happening at the molecular level to cause it. (a) the speed of sound in air (b) the current in a wire THANKS
48. ### physics

A 55.0-kg skydiver free falls for a period of time before opening his parachute. What is his kinetic energy when he reaches a velocity of 16.0 meters/second?
49. ### physics

A 55.0-kg skydiver free falls for a period of time before opening his parachute. What is his kinetic energy when he reaches a velocity of 16.0 meters/second?
50. ### physics

A Corvette, initially traveling at a speed of 6 m/s, speeds up (accelerates) at a rate of 0.2 m/s2 for 3 s. How far does it travel during that time? I tried d=vi*t-.2*t^2 but I did not get the correct answer
51. ### Physics

Find the average velocity over the time interval from 1 to 3 seconds. Express your answer in meters per second to the nearest integer.
52. ### physics

A large merry-go-round completes one revolution every 10.5 s. Compute the acceleration of a child seated on it, a distance of 5.20 m from its center. what is the magnitude?
53. ### physics

what sould be the angular speed with which the earth have to rotate on its axis so that a person on the equator would weight 3/5th as much as present..??
54. ### Physics with Calc

A point charge of 1.8uC (microcoulumbs) is at the center of a Gaussian cube 55 cm on edge. What is the net electric flux through the surface?
55. ### Physics

A Jet has a liftoff speed of 160 km/hr. What minimum uniform acceleration does this require if the aircraft is to be airborne after a takeoff run of 300m?
56. ### physics

Two stars, a binary star system, with a mass of m1 = 5.88E29 and m2 = 2.27E30 kg are separated by a distance of 2.55E11 m. What is the gravitational force between them?
57. ### physics

how does mass energy relate to the hydrogen bomb? i can't find anything that simply explains this to me and i need6 it for a powerpoint presentation tomorrow please help.
58. ### Physics

an airplane travels due north at 500km/hr there's a cross wind of 100km/hr determine the displacement of the air craft after 1 hour
59. ### physics

Two small metal spheres with masses 2.0 and 4.0 are tied together by a 5.4--long massless string and are at rest on a frictionless surface. Each is charged to +2.4 .
60. ### physics

7.If a washing machine's drum has a radius of 28 cm and spins at 4.1 rev/s, what is the strength of the artificial gravity to which the clothes are subjected? Express your answer as a multiple of g.
61. ### Physics

Two objects attract each other gravitionally with a force of 2.5 *10^-10 N when they are .25m apart. Their total mass is 4.0kg. Find their individual masses.
62. ### physics

If a washing machine's drum has a radius of 24 cm and spins at 4.1 rev/s, what is the strength of the artificial gravity to which the clothes are subjected? Express your answer as a multiple of g.
63. ### physics

How long would a 150 W lightbulb have to glow to produce the same amount of energy expended by Georgie? Answer in units of s.
64. ### physics

Question part Points Submissions 1 2 0/1 0/1 0/10 0/10 Total 0/2 A 3.5-kg block slides with a speed of 1.6 m/s on a frictionless, horizontal surface until it encounters a spring.
65. ### physics

A loaded truck can accelerate at 6.4 m/s^2. It loses its load so that it is only 0.9 as massive. By what factor must the acceleration change for the same driving force?
66. ### physics

A loaded truck can accelerate at 6.4 m/s^2. It loses its load so that it is only 0.9 as massive. By what factor must the acceleration change for the same driving force?
67. ### physics

A skydiver jumps out of a plane. Does the mechanical energy of the jumper change while she is falling? Ignore the effects of air resistance.
68. ### Physics

The constant torque required to accelerate a disk (of rotational inertia I) from rest to a speed of f rotations per second in a time interval of t is:
69. ### physics

Explain how you can tell the following statement is false A neutron was moving in a circle while speeding up. As a result, gamma rays were emitted.
70. ### physics

Explain how you can tell the following statement is false A neutron was moving in a circle while speeding up. As a result, gamma rays were emitted.
71. ### physics

an thelet completes one round of circular track of diameter 200m in 40 secomds. wht will be the distance covered t the end of 2min & 20 s.
72. ### physics

electricity is measured in kilowatts-hours, kW*h. this quantity can be converted to which other unit that measures energy? a.Pascals b.Joules c.Newtons d. Watts
73. ### physics

How much force is the air exerting on the front surface of the book with dimensions 19 x 27 cm. Assume atmospheric pressure equal to 100,000 Pa.
74. ### physics

If a burning log is a black object with a surface area of 0.35 m2 and a temperature of 800 ˚C, how much power does it emit as thermal radiation?
75. ### Physics

A 120-V rms voltage at 1000 Hz is applied to a resistor and an inductor in series. If the impedance of this circuit is 110 Ù, what is the maximum value of the current?
76. ### Physics

Suppose that you want to take a photograph of yourself as you look at your image in a flat mirror 1.6 away. For what distance should the camera lens be focused?
77. ### physics

How much power is used by a 50Kg athlete in climbing a 10m high ladder in 9.8 sec? 1000 J 2000 J 3000 J 4000 J
78. ### Physics

German silver wire has a cross-sectional area of 2.047 x 10^-3 cm^2. How many meters are needed to make a resistance of 100 (omega)? I don't know where to begin.
79. ### physics

which of the following properties of a sound wave determines its pitch: wavelength, speed, amplitude, or frequency? Plese show work, Thank you, Silly
80. ### Physics

A Saturn V rocket with an Apollo spacecraft attached has a combined mass of 2.1 105 kg and will reach a speed of 11.2 km/s. How much kinetic energy will it then have?
81. ### Physics

With an average acceleration of −2.2 m/s^2, how long will it take a cyclist to bring a bicycle with an initial speed of 14.5 m/s to a complete stop? Answer in units of s.
82. ### physics

need help with tthe first question on this page!!! please mail.rdcrd.ab.ca/~smolesky/FOV1-000293AF/5Matter/PracticeWritten.pdf
83. ### physics

the 3 lb block A rests on a surface for which the coefficient of kinetic is Mk=.30 determine the distance the 8-lb cylinder B must descend so that A has a speed of Va = 5ft/s starting from rest.
84. ### science(physics)

the sum of three forces f1=100n, f2=80n, f3=60n acting on a particle is zero. The angle between f1 and f2 is: Please solve
85. ### physics

As a baseball is being caught, its speed goes from 30 to 0 m/s in about 0.005 its mass is 0.145. A) What is the baseballs acceleration in m/s^2 and in g's? B) What is the size of force acting on it?
86. ### physics

how the frequency of the sound produced will change in the case of aluminium sting of length 15cm when the string is tied between two ends
87. ### physics

A 1000 Kgs Vehicle moving with a sppeed of 20 meter per sec. is brought to rest in a distance of 50 metres. find the acceleration
88. ### Physics

Hi, Which correctly expresses the relationship between wavelength (L), speed (V) and perios (T) of a sinusodial wavform ? a) L = T/V b) L= 2fxV/ T c) L= 1 / V x T D) L= V/T e) L = V x T f) L= V x T/ 2f I feel it is option (d) ..please check for me .. and thanx
89. ### physics

Find the magnitude and direction of the net electrostatic force exerted on the point charge q3 in the figure below, where q = +2.5 μC and d = 28 cm. The picture is of a square. q1=+q, q2=-2q, q3=-3q, q4=-4
90. ### physics

Find the magnitude and direction of the net electrostatic force exerted on the point charge q3 in the figure below, where q = +2.5 μC and d = 28 cm. The picture is of a square. q1=+q, q2=-2q, q3=-3q, q4=-4
91. ### Physics

How much work is done to move a 1400 kg car from rest to 25 m/s.If this takes place over a distance of 130 m, what is the average net force?
92. ### Physics

Measurements can be described as accurate and/or precise. Define accuracy and precision and give examples of how those terms could be used to describe a measurement.
93. ### science/physics

I was in a crosswalk, struck by a truck weighing 3,400 lbs. (traveling at about 8 K/hr) - what was the force per square inch exerted on me?
94. ### Physics

An austronaut orbits the Earth in the space shuttle, in one complete orbit, is the magnitude of thr displacement the same as the distance traveled?
95. ### Physics

Simpson drives his car with an average velocity of 45.1 km/h to the east. How long will it take him to drive 153 km on a straight highway? Answer in units of h
96. ### physics

Find the electric flux through each surface. (Use any variable or symbol stated above along with the following as necessary: ε0.)
97. ### physics

a car accelerates uniformly from rest to a speed of 21.8 km/h in 5.9 seconds.find the distance it travels during this time. answer in units of meters
98. ### physics

How far should and object be from a concave sperical mirror of radius 36cm to form a real image one-ninth it's size?
99. ### physics

a trench mortar fires a shell at an angle of 30 degrees with the horizontal and with a speed of 500 m/s. find its range and the maximum height it attains?
100. ### physics

Charge of uniform surface density (0.2 nC/m2) is distributed over the entire xy plane. Determine the magnitude of the electric field at any point having z = 2 m.