# physics please HELP !

74,851 results, page 83
1. ## physics science

Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
2. ## 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?
3. ## Physics

Find the length of an inclined plane that will reach a platform 8ft high and form 16degree with the ground
4. ## Grade 11 Physics - Light Unit

Why must rays be shone in the centre of a flat surface? Describe the difficulty that's results if this is not done.
5. ## physics

a rock with a mass of 2 kg is thrown from the top of a cliff 75 m high with a velocity of 10m/s. how much Kinetic energy does it have when it gets to the bottom?
6. ## physics science

Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
7. ## Physics

a 4.0 cm high object is placed 5.10 cm from a concave mirror whose redius of curvature is 21.2 cm. Find the inmage distance and the image size.
8. ## Physics

How much heat, expressed in Kwh, is required to raise the temperature of water in a 20,000 gallon pool by 10 degrees C. ?
9. ## physics

Find the limiting velocity of a rain drop assuming diameter of 5.0×10^-4m.The density of air relative to water is 1.3×10^-3
10. ## Life orentation,maths,physics,business,geography

Explain three ways in wich you can help to adress poverty and aids in s.a
11. ## physics

a fan rotates speed of 600rev per min the power is cut it stopped after 60 rev find time
12. ## physics

The car is travelling along the road with a speed of v  (300 / s) m/s, where s is in meters. Determine the magnitude of its acceleration when t = 3 s if t = 0 at s = 0. ( ans: a = 1.28 m/s2).
13. ## physics

Two freight cars, each with a mass of 2.5 multiplied by 10^5 kg, collide and stick together. One was initially moving at 3.4 m/s and the other was at rest. What is their final speed?
14. ## Physics

A car starts from rest and accelerates uniformly at 2m/s2 for 10 sec . Find the velocity and displacement at the end of 10 seconds .
15. ## Physics

Two ants race across a table 58cm long. One travels at 4.8 cm/s and the other at 3 cm/s. When the first one crosses the finish line, how far behind is the second one? Answer in units of cm
16. ## Physics

Show that 480 W of power is expended by a weightlifter when lifting a 60-kg barbell a vertical distance of 1.2 m in a time interval of 1.5 s.
17. ## Physics

What is the gravitational field strength at a place 220km above Earth's surface, the altitude of many piloted space flights?
18. ## physics

What is the acceleration (in meters/second^2) of a freely falling 74.0 kg sky-diver, if air resistance exerts a force of 264 N?
19. ## Physics

Calculate the torque on a coil in a motor of length 0.2m and a width of 0.1m which carries a current of 5A placed in a magnetic field of 0.5T and has 1 turn.
20. ## Physics

Suppose a cube that measures 0.020 m on each side were made of water. Find its volume, mass, and weight.
21. ## physics

A particle (p) moves along the curved surface (s). Show that p will remain in contact with s provided that at all times its speed v≥√rgcosteta.
22. ## physics

You are driving north on a highway. Then, without changing speed, you round a curve and drive east. Does your velocity change?
23. ## Physics

How much work is done by a boy weighing 450. Newtons while carrying a 20.0 kilogram package up a 2.00 meter flight of stairs?
24. ## physics

A pendulum has a mass of 3-kg, a length of 2 meters and swings through a (half)arc of 27.3 degrees. What is its Amplitude to the nearest centimeter ?
25. ## Physics

What types of material would be a good choice to shield a sensitive electronic device from stray electric fields?
26. ## physics

If a flea can jump straight up to a height of 0.310 m, what is its initial speed as it leaves the ground? How long is it in the air?
27. ## Physics

If a space station must "provide one sixth the magnitude of the acceleration due to gravity on Earth" Can I use 9.81ms^-2/6 or is that too simple? Thanks.
28. ## physics

A barometer is taken from the base to the top of a 554 m tower. Assuming the density of air is 1.29 kg/m3, what is the measured change in pressure?
29. ## physics

A uniform steel chain 20 m long and with a mass of 5 kg per m, hangs vertically. Compute the work required to wind it up
30. ## Physics

Computer the power output in watt of a machine that lift a 50kg crete through a height of 20cm in 1minute
31. ## Physics

Calculate the net charge on a substance con- sisting of a combination of 1.9 × 10^13 protons and 3.9 × 10^13 electrons. Answer in units of C.
32. ## physics

calculate the horizontal force that must be applied to produce an acceleration of 72 m/s^2 for a 0.034 kg punk on a friction less air table
33. ## Physics

A pendulum has a mass of 3.2 kg, a length of 2 meters and swings through a (half)arc of 28.1 degrees. What is its amplitude to the nearest centimeter?
34. ## physics

Calculate how many joules of energy would be needed to take 2kg of ice at -5 and turn it all to steam at 100 degees celcius?
35. ## Physics

Where must an object be placed to have a magniﬁcation of 3.74 in front of a converging lens of focal length 14.1 cm? Answer in units of cm
36. ## physics 11

a small 900kg sports car can deliver 100Hp to the pavement. how quickly can it reach 30m/s from rest?
37. ## physics

How do the pressure variations with depth affect our ability to explore the ocean? Consider the challenges of scuba diving and submarines.
38. ## physics

A 4.2 kg mass undergoes an acceleration given by ~a = ax ˆı + ay ˆ , where ax = 0.6 m/s 2 and ay = 4.8 m/s 2 . Find the magnitude of the resultant force. Answer in units of N
39. ## Physics

The displacement from the equilibrium caused by a wave on a string is given by: y(x,t) = (-0.00200 m)sin[(40m^-1)x-(800s^-1)t]. What is the number of waves in 1 m?
40. ## Physics

If a person jumped off the side of a ship from 20 feet high what speed would they be travelling at when they impact the water? Thanks Mike
41. ## Physics

In grandpa’s time automobiles were previously manufactured to be as rigid as possible, whereas autos are now designed to crumple upon impact. Why? Please help; Thank you in advance for the help...
42. ## physics

Charge polarization is normally produced by ____________________. A) nuclear interactions.B) contact.C) induction.D) friction.E) electrostatic means.
43. ## physics

An object is dropped from a platform 400 ft high. Ignoring wind resistance, how long will it take to reach the ground?
44. ## Physics

If Galileo and his assistant were 16 km apart, how long would it take light to make the round-trip? How does this time compare with reaction times of about 0.4 s?
45. ## Physics

What is gravitational force of a 65kg person that is on the surface of the moon has a mass of 7.348 x 10^22kg and radius of 1731km?
46. ## physics

Five forces act on an object. (1) 57 N at 90° (2) 40 N at 0° (3) 77 N at 270° (4) 40 N at 180° (5) 50 N at 60° What are the magnitude and direction of a sixth force that would produce equilibrium?
47. ## 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?
48. ## Physics

A baseball was hit at 45m/s at an angle of 45 degrees above the horizontal. How long did it remain in the air? How far did it travel horizontally?
49. ## physics

a toy moves on a horizontal surface with a speed of 3m/s.it makes 8 turns in 5 seconds,whats the diameter of the wheel?
50. ## physics

three resistors of 2ohm, 3ohm and 4 ohm are connected in (a) series (b) parallel. find the equivalent resistance in each case
51. ## physics

a man holds a child on his shoulders while watching a football match. How much work has he done if the game lasts for 2 hours
52. ## physics

A female gymnast weighs 200 N. If she is hanging stationary from a high bar,how many forces are acting on her? A. one B.five C.four D.two E.three WOuld it be choice A or D?
53. ## physics

A ball is thrown directly downward with an initial speed of 8.95 m/s, from a height of 29.0 m. After what time interval does it strike the ground?
54. ## Physics

The materials with the lowest resistance are called a) conductors b)superconductors c)semiconductors d) insulators I can't decide between a) or b) but if I had to choose one would the correct one be b)?
55. ## physics

Solid and hollow cylinders both roll from rest down an inclined plane. Explain the difference in speeds at the bottom.
56. ## Science - PHYSICS

im having problem understanding what motion equation to use. " A motercycle moving 12 m/s [W] accelerates at 6.0 m/s [W]. How long will it take to experience a displacement of 63 m [w] ? "
57. ## Physics

consider a cart being pulled up an inclined plane by a student during a Physics lab. The applied force on the cart is 18 N is directed parallel to the incline to cause the cart to be displaced parallel to the incline for a given displacement of 0.7 m. The
58. ## Physics

consider a cart being pulled up an inclined plane by a student during a Physics lab. The applied force on the cart is 18 N is directed parallel to the incline to cause the cart to be displaced parallel to the incline for a given displacement of 0.7 m. The
59. ## Physics repost please check

Posted by Mary on Monday, November 5, 2007 at 8:19pm. A charged particle, passing through a certain region of space, has a velocity whose magnitude and direction remain constant. (a) If it is known that the external magnetic field is zero everywhere in
60. ## physics

Biophysics strikes back The Biophysics students are having their usual Saturday night biophysics party performing physics experiments at a classmate’s home. This Saturday it is in an apartment building and you notice a managemnt student (MS) passed out
61. ## Physics please check repost

The pressure and volume of a gas are changed along a path ABCA in the figure. The vertical divisions on the graph represent 4.0 x 10^5 Pa, and the horizontal divisions represent 4.5 x 10^-3 m3. The diagram is a upright rectangle divided into small squares
62. ## Physics please clarify

A charge of -3.00 µC is fixed at the center of a compass. Two additional charges are fixed on the circle of the compass (radius = 0.135 m). The charges on the circle are -3.20 µC at the position due north and +5.00 µC at the position due east. What is
63. ## physics

A physics student pulls a block of mass m = 23 kg up an incline at a slow constant velocity for a distance of d = 4 m. The incline makes an angle q = 25° with the horizontal. The coefficient of kinetic friction between the block and the inclined plane is
64. ## Physics

A certain number of identical resistors are connected in series and their total resistance is measured. When the resistors are disconnected and re-connected in parallel, their total resistance drops to one-percent of the value measured when they were
65. ## physics

A physics student pulls a block of mass m = 20 kg up an incline at a slow constant velocity for a distance of d = 4.5 m. The incline makes an angle Δ = 30° with the horizontal. The coefficient of kinetic friction between the block and the inclined
66. ## physics

A pump slowly lifts 3.0*10^6 kg of water an average distance of 80.0m in 12minutes. 1) how much work is done in the first 12 minutes? 2)How much power is delivered by the pumps?
67. ## Physics

What is the wavelength of a radar signal that has a frequency of 30 GHz? The speed of light is 3 × 10^8 m/s. Answer in units of m Giving me the formula is just fine
68. ## Physics

A bicycle with tires 64 cm in diameter travels 5.2 km . Part A How many revolutions do the wheels make? Express your answer using two significant figures.
69. ## physics

a gazelle attempts to leap a 2.1m fence. assuming a 45 degree takeoff angle, whats the min speed for the jump
70. ## physics

At a construction site a pipe wrench struck the ground with a speed of 24 m/s. (a) From what height was it inadvertently dropped? (b) How long was it falling?
71. ## physics

If two wires P and O each of the same length and same material,are connected in parallel to a battery. The diameter of P is half that of Q. What fraction of the total current passes through P?(a)0.2(b)0.25(c)0.33(d)0.5
72. ## Physics

a 35 kg child slides down a 26 degree incline. the coefficient of kinetic friction is 0.33. what is her speed after sliding for 2.5 seconds starting from rest?
73. ## Physics

Suppose that two concentric rings, each with equal mass per unit length are joined so that they rotate together. Find the moment of inertia.
74. ## physics

What net torque is required to give a uniform 12-kg solid ball with a radius of 0.22m an angular acceleration of 12rad/s2 ?
75. ## physics

describe the force board experiment to show how to obtain the resultant of two non-parallel coplanar forces acting at a point.
76. ## physics

an object weighs 10N on earth .what is the objects weight on a planet one tenth the earths mass and one half its radius?
77. ## physics

If the coefficient of kinetic friction is 0.25 , how much horizontal force is needed to pull each of the following masses along a rough desk at a constant speed? A) 25 kg
78. ## physics

How much work must be done to roll a metal safe, mass 116 kg, a distance of 15.0 m across a level floor? The coeffecient of friction is 0.050.
79. ## PHYSICS

IF EARTH WERE TO ROTATE FASTER THAN ITS PRESENT SPEED THEN WEIGHT PF OBJECT WILL DECREASE AT EQUATOR BUT REMAIN UNCHANGED AT POLES why?
80. ## physics

a d'arsonval meter movement deflects to 0.8mA. what is the peak value of the alternating current if the instrument uses full-wave rectification?
81. ## Physics

A car whose brakes are locked skids to a stop in 200 ft from an initial velocity of 50 mi/hr. Find the coefficient of sliding friction.
82. ## Physics - Help!!!

I want to be sure I'm using the right formula for this question: Calculate the electric force between 2 electrons that are 5.3 x 10^-11 m apart (electron charge = -1.6 x 10^-19 C) I'm using the equation for Coulomb's Law: F = K (q1 q2)/d^2 (-1.6 x
83. ## Physics

Two positive charges one 2uc and the other 7uc are separated by a distance of 20cm, what is the magnitude of the electrostatic force that each charge exerts upon the other
84. ## Physics

A little girl is standing on a cliff and throws a ball straight down at a speed of 5m/s towards the ground below. How far has it fallen 2.0 seconds after it leaves her hand?
85. ## physics

an object is placed 10 cm from a concave spherical mirror whose radius of curvature is 12 cm. What is the distance of image a) 5cm b) 10 cm c)15cm d)20cm e)24cm
86. ## physics

a car cover 100 m in 5th second and 120 m in 8th second during its motion ?calculate the acceleration and distance covered in 20th second?
87. ## physics

A battery of emf and negligible internal resistance is connected to two resistances R1 and R2 in series. What is the potential difference across R2?(a)E(R1+R2)/R2(b)E(R1+R2)/R1(c)ER2/R1+R2(d)ER1/R1+R2
88. ## Physics

The coefficient of kinetic friction for a 22 kg bobsled on a track is 0.15. What force is required to push it down a 6.0° incline and achieve a speed of 64 km/h at the end of 75 m?
89. ## physics

what is the magnitude and the direction of an electric field when an electron is accelrated vertically upward at a distance of 5.5 metres in 3 micro seconds?
90. ## physics

If Joe rides south on his bicycle in a straight line for 26 min with an average speed of 11.6 km/h, how far has he ridden? Answer in units of km
91. ## PHYSICS

SIMPSON DRIVES HIS CAR WITH AN AVERAGE VELOCITY OF 48.0KM/H TO THE EAST. HOW LONG WILL IT TAKE HIM TO DRIVE 144KM ON A STRAIGHT HIGHWAY?
92. ## physics

Calculate the current that moves through your fingers (resistance 1000 \Omega) when you touch them to the terminals of a 6.4- V battery. please include the units
93. ## Physics

A triply ionized beryllium atom (Be3+) has only one electron in orbit about the nucleus. What is the radius of the ion when it is in the n = 9 excited state?
94. ## physics

Scalar product of three vectors? Given:A=(axi+ajy+azk) B=(bxi+bjy+bzk) C=(cxi+cjy+czk)
95. ## physics

A man whose mass is 75kg walks up a flight of 12 steps each 20 cm high in 5 seconds . Find the power he develops in watts
96. ## Physics

The power output of an elevator is 15000 W. How many persons could it carry if it raises passenger to a height of 35 m in 20 s ( each person has an average mass of 60 kg)?
97. ## physics

A racing car has a mass of 1970 kg. The acceleration of gravity is 9.8 m/s^2. What is its kinetic energy if it has a speed of 102 km/h? Answer in units of J.
98. ## physics

1. During storm roof of house is blown off 2.It is dangerous to stand near the railway track when a train is moving with high speed
99. ## Help- Physics

How much work did the movers do (horizontally) pushing a 130kg crate 10.1 m across a rough floor without acceleration, if the effective coefficient of friction was 0.50?
100. ## Physics

A player kicks a football from ground level with a velocity of magnitude 31.0 m/s at an angle of 30.0 degrees above the horizontal. What is its maximum height?