Physics - February 2007

A person is to be released from rest on a swing pulled away from the vertical by an angle of 15.8°. The two frayed ropes of the swing are 2.75 m long, and will break if the tension in either of them exceeds 350 N.

What is the maximum weight the person can have and not break the ropes?

2007-02-21 16:49:26 · 2 answers · asked by Cando 3

2007-02-21 16:45:41 · 2 answers · asked by asdf 1

2007-02-21 16:10:01 · 1 answers · asked by sandeep g 1

Am I right? W=Fd, now if that is true then whenever force is negative, then the displacement is negative too.

2007-02-21 15:57:13 · 4 answers · asked by Theta40 7

2007-02-21 15:45:04 · 2 answers · asked by Anna B 1

2007-02-21 15:41:47 · 4 answers · asked by Anna B 1

when asked these 2 separate questions, what are you supposed to be thinking? I'm confused what's the difference between
a) are these forces equal and opposite?
b) are these forces an action-reaction pair?
examples would be great and use simplistic words to explain.

2007-02-21 15:33:23 · 2 answers · asked by soccerjock 2

my professor informed me about a mathamatical equation to prove that if you walked into the wall repeatedly you would eventually find yourself on the other side. do you think this is possible? have you heard about this theory?

2007-02-21 14:51:05 · 15 answers · asked by ? 4

A movie stuntman (mass 80.0 kg) stands on a window ledge 5.0 m above the floor. Grabbing a rope attached to a chandelier, he swings down to grapple with the movie's villain (mass 70.0 kg), who is standing directly under the chandelier. (Assume that the stuntman's center of mass moves downward 5.0 m. He releases the rope just as he reaches the villain.)

a) With what speed do the entwined foes start to slide across the floor?
b) If the coefficient of kinetic friction of their bodies with the floor is mu_k= 0.205 , how far do they slide?

2007-02-21 14:50:43 · 2 answers · asked by Paul Wall 2

2007-02-21 14:49:34 · 4 answers · asked by Jesse S 1

A rifle bullet with mass 8.00 g strikes and embeds itself in a block with mass 0.992 kg that rests on a frictionless, horizontal surface and is attached to a coil spring. The impact compresses the spring 15.0 cm. Calibration of the spring shows that a force of 0.750 N is required to compress the spring 0.250 cm

a) Find the magnitude of the block's velocity just after impact.
b) What was the initial speed of the bullet?

2007-02-21 14:48:19 · 3 answers · asked by Paul Wall 2

A rocket is fired in deep space, where gravity is negligible. In the first second it ejects (1/160) of its mass as exhaust gas and has an acceleration of 14.0 m/s^2

What is the speed v_gas of the exhaust gas relative to the rocket?

2007-02-21 14:45:00 · 2 answers · asked by Paul Wall 2

Two cars, both of mass m, collide and stick together. Prior to the collision, one car had been traveling north at speed 2v, while the second was traveling at speed v at an angle phi south of east. After the collision, the two-car system travels at speed v_final at an angle theta east of north.

What is the speed v_final of the joined cars after the collision

2007-02-21 14:41:59 · 2 answers · asked by Paul Wall 2

how it is made or produce

2007-02-21 14:36:24 · 1 answers · asked by Elsa G 1

A pitcher throws a .142kg baseball at 47.2 m/s. As it travels a distance of 19.4m, the ball slows to 42.5 m/s because of air resistance. Find the change in temperature of the air through which the ball passes. The following assumptions may be made: molar specific heat of air is (7R/2), molar mass of air is 28.9 g/mole, and the cover insulates the interior of the ball so the ball's temperature does not change. The temperature change happens in a cylinder of 19.4m length and radius of 3.7cm. Air temperature is 20 degrees Celcius.

2007-02-21 14:35:33 · 1 answers · asked by Shane W 1

A 63 kg skier coasts up a snow covered hill that makes an angle of 25 degrees with the horizontal. The intial speed is 6.6 m/s, she coasts a distance of 1.9 m, the final speed is 4.4 m/s.
A) find the work done by the kinetic frictional force that acts on the skis.

B) what is the magnitude of the kinetic frictional force?

2007-02-21 14:12:25 · 3 answers · asked by Anonymous

The position vector = (5.40 t + (et + ft2) locates a particle as a function of time t. Vector is in meters, t is in seconds, and factors e and f are constants. Figure 4-34 gives the angle of the particle's direction of travel as a function of time ( is measured from the positive direction of the x axis). What are (a) factor e and (b) factor f, including units?
the angle =20 degree

2007-02-21 14:01:08 · 1 answers · asked by debelex10000 1

2007-02-21 13:49:18 · 2 answers · asked by timom 1

A horizontal force of 805 N is needed to drag a crate across a horizontal floor with a constant speed. You drag the crate using a rope held at an angle of 32 degrees.
a. What force do you exert on the rope?
b. How much work do you do on the crate when moving it 22m?
c. If you complete the job in 8 s, what power is developed?

Hope you guys can help me and explain to me how you got your solutions. Many thanks!

2007-02-21 13:42:37 · 3 answers · asked by Anonymous

an 8 meter scaffold supports a mason, bricks, and itself. The scaffold weighs 427N, mason A weighs 895 N, mason B weighs 1291 N and the bricks weigh 1620 N. From the left end of the scaffol, Mason B is 2 M the bricks are 5m and mason A is 7.25M. The scaffold is uniform. In order to establish equilibrium what must the upward force on each end of the scaffold be?

2007-02-21 13:38:16 · 1 answers · asked by rogue chedder 4

Energy added to a system

a)does work or increases thermal energy
b)cannot heat the environment
c)is converted to radiation
d)reduces the kinetic energy of the system



Which occurs just before ignition?

a)intake stroke
b)compression stroke
c)exhaust stroke
d) power stroke

2007-02-21 13:37:38 · 3 answers · asked by maconheira 4

a 60 kg boy sits 1.8 meters from the pivot point (left end) on a teeter totter which has a mass of 15 kg. the tetter totter is 4 meters long. Where must a 49 Kg girl sit in order for the teeter totter to balance.

2007-02-21 13:32:50 · 1 answers · asked by rogue chedder 4

Hey guys! I hope you can help me with these two physics problems. I really do appreciate it.:)

1) Brutus, a champion weightlifter raises 240 kg of weights a distance of 2.35 m.
a. How much work is done by Brutus lifting the weights?
b. How much work is done by Brutus holding the weights above his head?
c. How much work is done by Brutus lowering them back to the ground?
d. Does Brutus do work if he lets go of the weights and they fall back to the ground?
e. If Brutus completes the lift in 2.5 s, how much power is developed?

2) A force of 300 N is used to push a 145 kg mass 30 m horizontally in 3 s. Calculate the work done on the mass and the power developed.

Thanks! And can you please explain to me how you got the answers? :)

2007-02-21 13:22:04 · 3 answers · asked by happygolucky! 1

Is steam lighter or heavier than air? Anyone ever heard of a hot steam baloon? I'm just curious if it is even possible. Thanks.

2007-02-21 13:21:57 · 8 answers · asked by rykker 3

Even though thay are the same temperature. Shouldn't it be the other way around?

2007-02-21 13:19:08 · 2 answers · asked by Anonymous

If you used a substance like maple syrup instead of water in a graduated cylinder, what factors would be affected and how would you have to change them to make the Cartesian Diver in syrup work?

2007-02-21 13:14:47 · 1 answers · asked by hintzruby 1

Why isn't a coffee stain uniform in color and concentration?

2007-02-21 13:02:33 · 3 answers · asked by Anonymous

2007-02-21 12:49:20 · 4 answers · asked by Anonymous

By JUST looking; no asking. Any ways to tell?

2007-02-21 12:45:13 · 7 answers · asked by Anonymous

i was looking for a video/ movie/ documentary i can get or watch online about quantum mechanics.
any help?

2007-02-21 12:41:53 · 2 answers · asked by me 4