Physics - September 2007

Velocity is speed and direction.
Speed is just... speed.

My dilemma is this: If you drop two objects and there is no air resistance, they WILL fall at the same speed. However, is it or is it not relevant that they will also fall in the same direction (i.e. velocity)?

Any help with this Physics questions is greatly appreciated. Thanks in advance!

2007-09-10 16:50:03 · 10 answers · asked by Anonymous

...deg. above the horizontal. the building is 13.9m in height. accelertation of gravity 9.8m/s2. at what horizontal distance, from the base of the building will the rock strike the ground in meters?

2007-09-10 16:34:49 · 2 answers · asked by ? 1

Physics Problem Trouble?
A seagull, ascending straight upward at 4.40 m/s, drops a shell when it is 15.5 m above the ground.

The magnitude and direction of the shell's acceleration just after it is released is 9.8 m/s^2 downward.

The maximum height above the ground reached by the shell is 16. 487755 m.

A. How long does it take for the shell to reach the ground?

B. What is the speed of the shell at this time?

HELP I am totally at a loss! I got that the max height is 16.487755, but I can't figure out the next two parts.

2007-09-10 16:18:26 · 4 answers · asked by lstntht 1

In the movie Matrix, when a flying bullet is shown in slow motion, it emits some kind of rings behind it. Does a it really do that in real life, if the bullet is seen in slow motion, or is that just an “imaginary” effect for movies only? (And if it is real, then what makes it do that?)

Also this is a random question, but do you have any idea why this special effect (for the movie) is named as “bullet time?” I was just curious if anyone knew.

2007-09-10 16:16:32 · 3 answers · asked by ? 1

A basketball player, standing near the basket to grab a rebound, jumps 76.0 cm vertically. How much total time does the player spend (a) in the top 15.0 cm of this jump and (b) in the bottom 15.0 cm? Does this help explain why such players seem to hang in the air at the tops of their jumps? Show and explain your work. Thanks and good luck! :)

2007-09-10 16:15:23 · 1 answers · asked by Anonymous

(2.3 x 10^4) + (2.0 x 10^-3)=
I know that i must make the exponents the same,but i don't know if i'm doing it right.
please tell me how to do it (by hand plz)

also is this right?
(2.67 x 10^-3) - (9.5 x 10^-4)

2007-09-10 16:11:59 · 1 answers · asked by Anonymous

2007-09-10 15:48:25 · 2 answers · asked by skulltra_02 1

Warp 1.71 = 5.00 times the speed of light; speed of light =3.00 * 10^8m/s; 1 knot = 2000 yd/h, exactly

2007-09-10 14:44:33 · 1 answers · asked by Sina 2

from the top of cliff, a person uses slingshot to fire a pebble downward--the negative direc. the initial speed of the pebble is 9 m/s. a)what is the acceleration [magnitude+direction] of the pebble durng downward motion? is the pebble deacclerating? B) after .50 seconds, how far beneath the cliff top is the pebble?

2007-09-10 14:41:37 · 1 answers · asked by OMG. 2

why is it essential that all measurements be accompanied by appropriate units?

2007-09-10 14:29:43 · 2 answers · asked by lippypout 3

1. A diver running 1.7 m/s dives out horizontally from the edge of a vertical cliff and 3.0 s later reaches the water below.

How high was the cliff? ... m

How far from its base did the diver hit the water?.... m

2. A ball is thrown horizontally from the roof of a building 52 m tall and lands 45 m from the base. What was the ball's initial speed?

3. A batter hits a fly ball which leaves the bat 0.90 m above the ground at an angle of 57° with an initial speed of 29 m/s heading toward centerfield. Ignore air resistance.

(a) How far from home plate would the ball land if not caught?
(b) The ball is caught by the centerfielder who, starting at a distance of 105 m from home plate, runs straight toward home plate at a constant speed and makes the catch at ground level. Find his speed.

2007-09-10 14:16:06 · 1 answers · asked by Nikita 1

Extremely bright green laser at 532 nm wavelength

Output power of <5mW (Class IIIa Laser Product)

What does all of this mean?
How do you know if you can see it in the air?

2007-09-10 14:04:34 · 3 answers · asked by Anonymous

A cord is used to vertically lower an initially stationary block of mass M kg at a constant downward acceleration of g/4. The block has fallen a distance d.

(a) Find the work done by the cord's force on the block. (Answer in terms of M, g, and d.)

(b) Find the work done by the weight of the block.

(c) Find the kinetic energy of the block.

(d) Find the speed of the block. (Assume the positive direction is downward.)

2007-09-10 13:47:54 · 2 answers · asked by Kristen B 1

A crate of mass 36kg is released from the top of a ramp. The ramp is 2.5m lang and inclined at an angle of 0 (theta) to the horizontal, where sin 0 (theta) =3/5. As the crate reaches the bottom of the ramp, it gains a speed of 4.5m/s.

(a) Calculate the gain in kinetic energy.
(b) Calculate the loss in potential energy.
(c) Compare the results in (a) and (b), and show that some other form/s of energy must have been produced.
(d) What is the nature and size of the other form/s of energy in (c)?
(e) Calculate the friction between the crate and the ramp.
(f) Find the work done by gravitational force.

2007-09-10 13:28:52 · 1 answers · asked by Anonymous

i was just wondering because the mirror always has a left/right reversal of your image.

2007-09-10 13:22:14 · 4 answers · asked by neener 2

2007-09-10 13:19:49 · 1 answers · asked by Red 2

A solid sphere having a volume of 1.00 m^3 fits tightly in a cubical box. What is the volume contained within the box?

2007-09-10 13:12:58 · 2 answers · asked by dontknowphysics 1

An astronaut has left the International Space Station to test a new space scooter. Her partner measures the following velocity changes, each taking place in a 15 s interval. What are the magnitude, the algebraic sign, and the direction of the average acceleration in each interval described below? Assume that the positive direction is to the right.

(a) At the beginning of the interval the astronaut is moving toward the right along the x-axis at 14.0 m/s, and at the end of the interval she is moving toward the right at 4.0 m/s.
Magnitude
_______m/s and direction

(b) At the beginning she is moving toward the left at 4.0 m/s, and at the end she is moving toward the left at 15.0 m/s.
Magnitude
______m/s

(c) At the beginning she is moving toward the right at 14.0 m/s, and at the end she is moving to the left at 14.0 m/s.
Magnitude
_____m/s and direction.

2007-09-10 13:03:44 · 1 answers · asked by Anonymous

Two cars travel westward along a straight highway, one at a constant velocity of 87 km/h and the other at a constant velocity of 113km/h.
A) assuming that both cars start at the same point, how much sooner does the faster car arrive at a destination 16 km away?
B) How far must the cars travel for the faster car to arrive 20 min before the slower car?
i've done the part A but stuck at the B one, so plz help me w/ the part b

2007-09-10 13:03:00 · 1 answers · asked by kimn 1

I know that Electromagnetism is stronger than Gravity, but by how much?

2007-09-10 12:48:18 · 3 answers · asked by tennisguy 1

Obviously, you can't drop a teabag into a 1-liter jar and expect 1 liter of tea. During the process of steeping, tea "particles" flow from the bag to the water. What stops this flow? Some sort of osmotic equilibrium? Do the leaves simply run out of "particles" to give?

2007-09-10 12:37:27 · 3 answers · asked by Anonymous

Does a car speedometer measure speed, velocity, or both?

2007-09-10 12:31:09 · 2 answers · asked by nirmal 1

the compressed air/c02. this impact drives the paintball out the barrel. my question is why isnt the paintball driven by say a butterfly valve opening and allowing the gas to expand and push the ball out the barrel. it would seem more efficent to have the ball driven by direct expanding gas, like a car piston, if you could get the sealing right. rather than have it struck by a piston, and deal with frictional losses, etc. can someone explain to me what im missing?

2007-09-10 12:02:35 · 3 answers · asked by mrx 1

(a) the side opposite the 20.0° angle ?

(b) the side adjacent to the 20.0° angle?

2007-09-10 11:58:43 · 2 answers · asked by Foxychick 1

I posted earlier, but I'm stuck on this one ......I'm having trouble with velocity and how to find the displacement. I know the formula, but I dont know how to find it within the questions. Help me out with this question, give me the formula, and plug in the numbers to get the answer. Thanks

1. An athlete swims from the north end to the south end of a 50.0 m pool in 20.0 s and makes the return trip to the starting position in 22.0 s. a.)What is the average velocity for the 1st half on the swim. b.) Average velocity for the 2nd half of the swim. c.) Average velocity for the roundtrip?

2007-09-10 11:58:31 · 1 answers · asked by neverisenough 1

Given the equations x= x(sub 0) + v(sub 0)Xt + 1/2XaXt^2 and v= v(sub 0) + aXt (where the capital X means multiplied by) show that an expression for v that has no explicit dependence on time (i.e. the variable t does not appear in the equation) can be written as v = SquareRoot of V(sub 0)^2 + 2XaX(x-x(sub 0))

2007-09-10 11:56:14 · 1 answers · asked by Mick T 1

2007-09-10 11:50:20 · 1 answers · asked by baby angel 1

A: T2 / L

B: L / T2

C:L * T2

D:L / T

E: L2 / L

2007-09-10 11:49:37 · 1 answers · asked by Foxychick 1

A boy sledding down a hill accelerates at 1.20 m/s2. If he started from rest, in what distance would he reach a speed of 9.50 m/s?

please show equation used and how you got the answer

2007-09-10 11:00:52 · 3 answers · asked by Anonymous

A 75kg person stands in an elevator. what force does the floor exert on the person when the elevator
(1) starts moving upward with an acceleration of 1.5 m/sec^2?
(2) moves upward with a constant speed of 2.0 m/sec?
(3) starts accelerating downward at 1.5 m/sec^2?
(b) If the person were standing on a bathroom (spring) scale during the ride, what readings would the scale have under conditions (1), (2), and (3) above.
(c) It is sometimes said that the "apparent weight" changes when the elevator acclerates. what could this mean? Does the weight really change?

2007-09-10 10:53:11 · 1 answers · asked by DJ Ott 1