Physics - December 2007

a(t)=-32 ft/sec squared. An object is thrown vertically down from the top of a 480 foot building with an initial velocity of 64 feet/second.What is the objects velocity right before it hits the ground?

2007-12-04 12:31:02 · 3 answers · asked by jo l 1

I've already asked this before but I am looking for a better explanation. It is an infinity sign, and looks like part of the right loop is chopped off. What does it mean?

I am taking Grade 11 physics so please don't confuse me too much. Thanks.

2007-12-04 12:26:20 · 1 answers · asked by myname_isalbert 1

2007-12-04 12:12:51 · 3 answers · asked by dunno22222222222222222 1

2007-12-04 12:00:10 · 1 answers · asked by lilprincess_2good4u 1

An aluminum cup with mass 0.55 kg holds 0.81 kg of water. Both the cup and the water have a temperature of 25.87 °C. If a 0.67-kg piece of copper at 76.9 °C is added to the cup, what is the final equilibrium temperature in °C? You may assume that the cup, water, and copper are well insulated from anything else.

2007-12-04 11:55:32 · 1 answers · asked by lilprincess_2good4u 1

In an insulated Styrofoam cup are mixed 0.59 kg of water at 23.48 °C and 0.13 kg of copper at 85.79 °C. Give the equilibrium temperature in °C.

2007-12-04 11:54:51 · 1 answers · asked by lilprincess_2good4u 1

I don`t even know if I wrote the qestion down right lol

2007-12-04 11:40:36 · 4 answers · asked by Jenny E 1

The height of a certain waterfall is 33.3 m. When the water reaches the bottom of the falls, its speed is 25.8 m/s. Neglecting air resistance, what is the speed of the water at the top of the falls?

2007-12-04 11:06:22 · 1 answers · asked by Anonymous

What would happen if protons would move and not electrons?

2007-12-04 10:55:57 · 1 answers · asked by Mariela V 2

A ball moving at 13.9 m/s makes an off-center elastic collision with another ball of equal mass that is initially at rest. The incoming ball is deected at an angle of 30.1deg from its original direction of motion. Calculate the velocity of the initially moving ball after the collision.

2007-12-04 10:52:46 · 1 answers · asked by mrjmiller21 1

Brass ball at rest is suspended on a rope. Tension in the rope is 6N.

What is strength of graviatation field (that is acceleration of gravity) created by the brass ball at the center of Earth?

Mass of planet Earth is 6e24kg.

2007-12-04 10:24:17 · 3 answers · asked by Alexander 6

Before the atom bomb was first exploded, the scientists thought about the possibility of setting the atmosphere on fire, or that the fission would spread. Similarly, partlcle physics research is on the edge of the unknown. It is at least possible that if the energy is high enough, we would release some catastrophic force.

Is the possibility being discussed?

2007-12-04 10:07:00 · 2 answers · asked by leo s 1

chapter 7 #29
a roller coaster car has a mass of 500 kg when fully loaded with passengers. if the vehicle has a speed of 20 m/s at point a (point a radius 10 meter) what is the force of the track on the vehicle at this point. what is the maximum speed the vehicle can have at point b (point b radius 15 meter) in order for gravity to hold it on the track.

2007-12-04 09:37:57 · 1 answers · asked by patelm61 1

Calculating the negative lift of an after market airfoil, on a car's trunk?
I'm having trouble doing a practice problem for my exam in physics. I have to take measurements on car's inverted airfoil or find some from the internet, Which seem impossible to find.

I need the path over top of the inverted airfoil, under it, and the length of the airfoil.



I then assume the wind is going 50 mph or 100mph while on the highway. - 22.32m/s and 44.704m/s


I need to calculate the velocity under the inverted airfoil, using the same approximation that the wright brothers used ( bernoulli's equaiton?"


From that , calculate the pressure difference between the top and bottom in Pascals. From that, calculate the force in newtons on the airfoil, then to pounds.


Any help would be appreciated, tried to find measurements on an airfoil for a few hours, can't find any. This problem is driving me insane.

2007-12-04 09:33:19 · 1 answers · asked by submsk 2

A 6.60 kg mass hanging from a spring scale is slowly lowered onto a vertical spring.

1) What does the spring scale read just before the mass touches the lower spring?

2) The scale reads 22.0 N when the lower spring has been compressed by 1.70 cm. What is the value of the spring constant for the lower spring?

3) At what compression length will the scale read zero?


ANY and ALL help is greatly appreciated. Thanks!

2007-12-04 09:30:18 · 1 answers · asked by Anonymous

A girl of mass M1 (60 kg) springs from a trampoline with an initial upward velocity (initial velocity = 8 m/s). At height 2 meters above the trampoline, the girl grabs a box of mass M2 (15 kg).

Assume 9.8 is the force of gravity.

The three questions:

1) What is the speed (v-before) of the girl immediately before she grabs the box? (Expressed in m/s)

2) What is the speed (v-after) of the girl immediately after she grabs the box? (Expressed in m/s)

3) What is the max height the girl reaches (this is measured with respect to the top of the trampoline)? (Expressed in meters)


Any and all help is greatly appreciated. Thanks! :)

2007-12-04 09:23:57 · 1 answers · asked by Anonymous

Why can't the manufacturers keep a decent inventory of these products on hand so there isn't a shortage every time they have a scheduled reactor shutdown?

2007-12-04 09:23:32 · 2 answers · asked by michinoku2001 7

Two ropes are used to lower a 255 kg piano 5.30 m from a second-story window to the ground. How much work is done by T1, T2, and B (in Joules)?

Info about these forces [T1 and T2 are on opposite sides].
T1 has a force of 1830 N and is 60º above horizontal.
T2 has a force of 1295 N and is 45º above horizontal.
B has a vertical force of 2500 N.

Absolutely ANYTHING will help. Thanks!

2007-12-04 09:18:40 · 1 answers · asked by Anonymous

chapter 8 #20
a 15 meter, 500 newton uniform ladder rests against a friction less wall making an angle of 60 degrees with the horizontal. find the horizontal and vertical forces exerted on the base of the ladder by the earth when an 800 newtons fire fighter is 4 meter from the bottom. if the ladder is just on the verge of slipping when the fire fighter is 9 meter up, what is the coefficient of the static friction between ladder and ground

2007-12-04 09:08:10 · 2 answers · asked by Don 1

a box rests on the back of a truck . The coefficient of ststic friction between box and truck bed is 0.300. When the truck accelerates forward what force accelerates the box. find the maximum acceleration the truck can have before the box slides

2007-12-04 08:57:23 · 2 answers · asked by Don 1

Would you more likely go to the past, or future?? And why?

2007-12-04 08:56:38 · 33 answers · asked by Anonymous

masses m1= 4 kg and m2=9 kg are connected by a light string that passes over a frictionless pulley. m1 is held at rest on the floor and m2 rests on a fixed incline of theta is 40 degrees. the masses are released from rest and m2 slides 1 meter down the incline in 4 seconds. determine the acceleration of each mass, the tension in the string and the coefficient of kinetic friction between m2 and the incline

2007-12-04 08:54:16 · 3 answers · asked by Don 1

a 150 newton bird feeder is supported by three cables . the cable is 30-60-90. find the tension in each cable.

2007-12-04 08:49:36 · 1 answers · asked by Don 1

2007-12-04 08:38:27 · 4 answers · asked by Black Rose 2

A 20.0 kg child slides down a 4.00 m-high playground slide. She starts from rest, and her speed at the bottom is 2.10 m/s.

What is the change in the thermal energy of the slide and the seat of her pants (in Joules)?

2007-12-04 08:36:47 · 1 answers · asked by Anonymous

2.Suppose an electric field with a magnitude of 2.8 E 4 N/C at a certain location, points due south. If a charge of -4.0 E -6 C is brought to the location, what is the electrostatic force that acts on this charge?

1.Matt forgot to put the fabric softener in the wash. As his socks tumbled in the dryer, they became charged. If a small piece of lint with a charge of +1.25 E -19 C is attracted to the socks by a force of 3.0 E -9 N, what is the magnitude of the electric field at this location?

2007-12-04 08:35:08 · 1 answers · asked by Goddess Allure 2

2007-12-04 08:07:14 · 10 answers · asked by Alexander 6

i'm having probs with E creates matter+ matter creates energy, why is there so much excess energy in the universe is the universe mostly energy or mostly matter, could be a serious q, what are the dimensions of energy, or the ratio of energy to matter, anyone?

2007-12-04 07:12:20 · 2 answers · asked by Book of Changes 3

2007-12-04 06:44:21 · 9 answers · asked by Anonymous

A bubble with a volume of 1.00 cm^3 forms at the bottom of a lake that is 30 m deep. The temperature at the bottom of the lake is 10°C. The bubble rises to the surface where the water temperature is 25°C. Assume that the bubble is small enough that its temperature always matches that of its surroundings. What is the volume of the bubble just before it breaks the surface of the water? Ignore surface tension. Units in cm^3

2007-12-04 06:35:08 · 1 answers · asked by Eli D 1