Physics - November 2007

I have heard about takeons which are supposed to travel faster than the speed of light. I thought that nothing could travel faster than this. Could someone please explain!

2007-11-30 08:27:03 · 3 answers · asked by Anonymous

A mini-golf course has a windmill that blocks the opening lower level of the course. The windmill has 4, 2 m long blades that are 25 cm wide at the ground and complete 2 revolutions per minute. If the ball starts from rest 10 meters away, what is the minimum speed with which you must strike the ball on level ground in order to have it pass between the blades?

2007-11-30 08:21:48 · 1 answers · asked by Anonymous

I don't know where to start from? Pls help if you know
Thanks!
Here is the problem:

Trying to beat the heat of the last summer, a physics student went to the local toy store and purchased a plastic child's swimming pool. Upon returning home, she filled it with 200 liters of water at 25oC. Realizing that the water would probably not be cool enough, she threw ice cubes from her refrigerator, each of mass 30g, into the pool. (The ice cubes were originally at 0oC.) She continued to add ice cubes, until the temperature stabilized to 16oC. She then got in the pool.
The density of water is 1000 kg/m3, the specific heat of water is 1.0 cal/g C, the specific heat of ice is 0.5 cal/g C, and the latent heat of fusion of water is 80 cal/g.


How many ice cubes did she add to the pool to get the temperature to 16 C? (Consider the pool and ice cubes an isolated system.)

2007-11-30 08:15:52 · 1 answers · asked by alra 2

I had to do Physics at college, and i'm struggling with my homework! Can anyone please help me and not just give me the answer- but explain how to do it so in future I can do it. Thankyou!

Large metal bars can be driven into the ground using a heavy falling object. The object (driving the bar into the ground) has a mass 2.0x10^3 kg and the metal bar has a mass of 400kg. The object strikes the bar at 6.0ms/-1. It comes to rest on the bar without bouncing. As a result of the collision, the bar is driven into the ground to a depth of 0.75 m.
(worth 4 marks)

(a) Determine the speed of the bar immediately after the object strikes it.
(3 marks)

(b) Determine the average frictional force exerted by the ground on the floor.

2007-11-30 08:03:09 · 2 answers · asked by Anonymous

Consider a 8.89-kg mass on the end of a linear spring in simple harmonic motion. The spring has spring constant 4.31 N/m. When the spring is maximally extended, it is 0.0156 m from the place in the oscillation where it is maximally compressed. The equilibrium position of the spring is midway between these two extremes. What is the mechanical energy of the mass in this oscillation? (Answer in J.)

2007-11-30 07:43:37 · 1 answers · asked by josh j 1

A 0.390 kg green bead slides on a curved frictionless wire, starting from rest at point A in Figure P6.52. At point B the bead collides elastically with a 0.600 kg blue ball at rest. Find the maximum height the blue ball rises as it moves up the wire. In m please! the figure is on this page: http://www.webassign.net/sercp/p6-52.gif

2007-11-30 07:41:30 · 1 answers · asked by Dave 1

A 10.0 g object moving to the right at 21.0 cm/s makes an elastic head-on collision with a 15.0 g object moving in the opposite direction at 31.0 cm/s. Find the velocity of each object after the collision. I need to find the velocity of the 10 g object and 15 g object.. in cm/s.. thanks!!

2007-11-30 07:37:08 · 3 answers · asked by Dave 1

Assuming atmospheric pressure to be 1.01 x 10^5 Pa and the density of sea water to be 1025 kg/m^3, what is the absolute pressure at a depth of 15m below the surface of the ocean?

2007-11-30 07:13:23 · 5 answers · asked by Anonymous

Two objects of masses m and 3m are moving towards each other along the x-axis with the same initial speed of v. The object with mass m is travelling to the left, and the object with mass 3m is traveling to the right. They undergo an elastic glancing collision such that m is moving downward after the collision at right angles from its initial direction. (a) find the final speeds of the two objects (b) What is the angle at which the object with mass 3m is scattered?

2007-11-30 06:41:28 · 2 answers · asked by Anonymous

What is the lift (in newtons) due to Bernoulli's principle on a wing of area 78 m2 if the air passes over the top and bottom surfaces of 260 m/s and 150 m/s respectively?

can you explain how to solve the problem? the teacher really didnt explain this part real well.

2007-11-30 06:34:04 · 2 answers · asked by Omar A 1

And why is it that there is a 0 probability of finding an electron at the node of the de Broglie wave?

Thank-you.

2007-11-30 06:24:28 · 3 answers · asked by Anonymous

3. You have a laser with wavelength = 635.3[nm]. The grating has a slit spacing of 1.633E-03[mm]. What is the angle measured for n=1?
angle = ___________[radian]
Use three sig. figs.; or use N/A, if not enough information is given.

2007-11-30 06:04:17 · 1 answers · asked by Anonymous

A U-tube open at both ends is partially filled with water (Fig. P9.80a). Oil ( = 810 kg/m3) is then poured into the right arm and forms a column L = 4.00 cm high (Fig. P9.80b).

Figure P9.80 http://www.webassign.net/sf/p9_80.gif

(a) Determine the difference, h, in the heights of the two liquid surfaces. Assume that the density of air is 1.29 kg/m3.
cm
(b) The right arm is then shielded from any air motion while air is blown across the top of the left arm until the surfaces of the two liquids are at the same height (Fig. 9.80c). Determine the speed of the air being blown across the left arm.
m/s

2007-11-30 06:03:21 · 2 answers · asked by Anonymous

A helium-filled balloon at atmospheric pressure is tied to a 3.0 m long, 0.070 kg string. The balloon is spherical with a radius of 0.40 m. When released, it lifts a length (h) of the string and then remains in equilibrium as in Figure P9.78. Determine the value of h. When deflated, the balloon has a mass of 0.25 kg. (Hint: Only that part of the string above the floor contributes to the load being held up by the balloon.)

http://www.webassign.net/sf/p9_78.gif < figure

2007-11-30 06:01:38 · 1 answers · asked by Anonymous

A skateboarder rides down the side of a half pipe that has a 25m diameter. He starts from rest and moves through an angle of 0.85 radians. If the skateboard has a wheel with a 2cm radius, how many rotations does each wheel make?

2007-11-30 05:55:14 · 2 answers · asked by Anonymous

Can that be translated into volt and amps....I can' really understand joules......Also , my defibrilator is internal so it functions more efficiently than external....I've had both.

2007-11-30 05:35:18 · 2 answers · asked by Anonymous

2007-11-30 05:32:07 · 5 answers · asked by paul w 1

A 1.5 kg mass is whirled in a horizontal circle at the end of a .8 meter long cord. If the cord stands out at an angle of 40 degrees from the vertical, calculate

(1) the radius of the circle produced by the path of the mass
(2) the angular speed of the mass in radians/second
(3) the centripetal force acting on the mass.

2007-11-30 05:20:45 · 1 answers · asked by labelapark 6

What mass of KNO3 would have to be decomposed to produe 21.1L of Oxygen measured at STP?

2007-11-30 05:18:18 · 1 answers · asked by youssef a 1

2007-11-30 05:15:17 · 4 answers · asked by bouncing_soul_geuse 2

The four tires of an automobile are inflated to a gauge pressure of 218000 Pa. Each tire has an area of 0.0297 m^2 in contact with the ground.
A. Determine the weight of the automobile. Answer in units of N.

2007-11-30 04:48:06 · 4 answers · asked by Anonymous

An engine works at 26% efficiency. The engine raises a 5-kg crate from rest to a vertical height of 8 m, at which point the crate has a speed of 4 m/s. How much heat input is required for this engine?

2007-11-30 04:47:31 · 3 answers · asked by Anonymous

A proton moves with a velocity of v = (2i - 4j + k)m/s in a region in which the magnetic field is B = (i + 2j - 3k)T. What is the magnitude of the magnetic force this particle experiences?

2007-11-30 04:46:57 · 3 answers · asked by andrew w 1

In a 47 s interval, 569 hailstones strike a glass window of area 0.624 m^2 at an angle 20 degrees to the window surface. Each hailstone has a mass 3 g and a speed 10.8 m/s.
A. If the collisions are elastic, find the average force on the window. Answer in units of N.
B. Find the pressure on the window. Answer in units of N/m^2.

2007-11-30 04:42:13 · 3 answers · asked by Anonymous

A 25kg child on a 2.0 m long swing is released from rest when the swing supports make an angle of 30.0 degrees with the vertical.

A) What is the maximum potential energy associated with the child?

B) Disregarding friction, find the child's speed at the lowest position.

C) What is the child's total mechanical engery?

D) If the speed of the child at the lowest position is 2.00 m/s, what is the change in mechanical energy due to friction?

*I would like to see how it is worked and what equations are used. Thanks

2007-11-30 04:42:03 · 1 answers · asked by Cambri 1

2007-11-30 04:38:18 · 19 answers · asked by k-monster 1

A wind with speed 45 m/s blows across a roof 20 m long and 12 m wide. The pressure inside the room is 1 atm. What is the net force on this roof due to the pressure difference inside and outside the roof? (The density of air is equal to 1.3 kg/m^3)

2007-11-30 04:24:57 · 1 answers · asked by emuhlee15 2

2007-11-30 04:06:57 · 5 answers · asked by Elijah W 1

1st and 2nd are width and height, the 3rd is depth and 4th is time. What is the 5th dimension?

I'll come back and give 10 points to the clearest answer.

2007-11-30 03:52:32 · 6 answers · asked by jack 6

2007-11-30 03:40:33 · 4 answers · asked by Shaq 2