Physics - October 2007

I just want to know what factors are realted to softball and what formulas apply to them. Thanx

2007-10-09 11:43:26 · 1 answers · asked by kraziikristie16 1

i'm talking about air guns, and rounds that don't connect with a person or a building. do they come back down to earth?

i know this probably has a really simple answer but i am very confused. have watched cop shows there they shoot into the air. and i was thinking... why doesn't the bullet come down. and managed to confuse myself

2007-10-09 11:01:35 · 34 answers · asked by maraesa1000 5

My problem is as follows: A sled is dragged along a horizontal path at a constant speed of 1.5 m/s by a rope that is inclined at an angle of 30.0° with respect to the horizontal (the figure below). The total weight of the sled is 470 N. The tension in the rope is 270 N. How much work is done by the rope on the sled in a time interval of 10.0 s? What equation would i use to figure this out? I cant seem to find one that also calculates work with tension of the rope.

2007-10-09 10:53:42 · 2 answers · asked by sportzblock 1

A cart slides down an inclined 1.44m long inclined ramp. The height of the ramp is .10m. The angle of the ramp is not given.

The work done by the friction is -.06. I need to figure out the value of the friction force acting on the cart. The formula I'm using is Work done by the friction = Friction force * d cos theta.

My problem is that since the problem doesn't provide the angle, I'm not sure what to use for theta - should I use 180 degrees because the friction force is acting in the opposite direction? Or should I use 4 degrees (by deriving the unknown angle by using sin theta = height/length of ramp).
Thank you for your help.

2007-10-09 10:36:06 · 2 answers · asked by Eva 1

V1x =
V1y =
V2x =
V2y =

(b) Determine the sum V1 + V2.
Magnitude

Direction
° (counterclockwise from the +x axis is positive)




? help please

2007-10-09 10:29:04 · 2 answers · asked by Shawn Carter 1

Do they mean "light moves in wave and not in a straight line'.?

2007-10-09 10:23:41 · 3 answers · asked by Padmini Gopalan 4

The figure shows a simple pendulum of length L = 54 cm and mass m = 2.4 kg. It's bob is observed to have a speed of vo = 4.8 m/s when the cord makes an angle θo = 24°.

What is the speed of the bob when it is in its lowest position?

What is the least value that v0 must have if the cord is to swing up to a horizontal position?

2007-10-09 09:55:51 · 1 answers · asked by borthausen 1

I have this 2kW electric heater at home that's well.....2kW. I found out that I'll never need to use it again, though. My gas furnace looks like a wood burning stove that just heats up a pipe that goes up to the roof. It takes forever to heat the house so I usually run a 2kW electric heater at the same time.

Anyway, recently got the idea to set up a fan to blow air on that pipe and now the room heats up 4 to 5 times faster. I guess I was losing a ton of heat just straight up and out through the roof. I looked at the fan label this morning and it was only 60 watts!!! The blade is like 2 feet in diameter and it's pretty powerful so it got me wondering. It seems like I'm getting something for nothing here.

So why is rotational energy draw so much less power?

2007-10-09 09:49:53 · 2 answers · asked by Anonymous

Most accurate answer gets 10 points. "Because it makes it colder" is not good enough.

2007-10-09 09:30:23 · 7 answers · asked by Scythian1950 7

Find the coefficient of rolling friction ?

2007-10-09 09:26:09 · 1 answers · asked by salvatore g 1

I am about to literally pay two runners to figure this out- anyway:

Runner A is initally 5.6km west of a flagpole and is running with a constant velocity of 8.8km/h due east.

Runner B is initally 4.9km east of the flagpole and is running with a constant velocity of 7.9km/h due west.

When they hit, how far will they be from the flagpole.

I keep getting 3.9!

2007-10-09 09:11:39 · 1 answers · asked by Anonymous

A fire helicopter carries a 773 kg bucket at the end of a 25.9 m long cable. When the helicopter is returning from a fire at a constant speed of 40.4 m/s, the cable makes an angle of 37.2 degrees with respect to the vertical.
The acceleration of gravity is 9.8 m/s/s.
Find the horizontal force exerted by air resistance on the bucket. Answer in units of N.

2007-10-09 09:10:36 · 1 answers · asked by lilprincess_2good4u 1

Suppose a golf ball has a mass of .05kg is hurled with a speed of 10 m/s at a heavy bowling ball of mass 1.5kg initially at rest and bounces elastically from the bowling ball.

Which ball has the greater momentum after collision. Why?
Which has the greater kinetic energy and why?

2007-10-09 09:00:06 · 2 answers · asked by txsweetpea512 1

The rear of a bicycle passes a point O on a road with a velocity 4ms-^1 and an acceleration of 2ms^1.4 seconds later the front of a car passes O with a velocity of 2ms-^1 and an acceleleration of 4ms-^1.How far from O does the front of the car meet the rear of the bicycle? Please help so may of times q's like these come up nd i cant do em

2007-10-09 08:55:04 · 1 answers · asked by the phenom 1

i know all this problems are easy but i am having hard time with my physic because i dont' understand physic,so plz help me as much as you can 1 or 2 is better than nothing =]

1.when representing velocity as a vector?
2.in order to find the components of a vector,you should....?
3.which of the following would not be considered a projectile?
4.the horizontal component of a projectile's velocity is independents of.....?
5.in the absence of air friction,the vertical component of a projectile's velocity doesn't change as the projectile moves?
6.in the absence of air friction, the horizontal component of a projectile's velocity doesn't change as the projectile moves..is true or some time true or alway false?
7.which best approximates the resultant of a pair of 10 unit vectors at right angles to each other?
8.when in orbit,a satellite like the space shuttle is....?

2007-10-09 08:46:30 · 2 answers · asked by some guy =] 3

I was assigned a sheet full of problems in physics class, and I got them all except these two. Could anyone help me please?

1. A car is stopped at a stoplight. As soon as it turns green, it accelerates 10 ft./s^2 while a truck that didn't stop, having a constant velocity of 30 ft./sec passes the car.

How far beyond the starting point will the car overtake the truck, and how fast will the car be traveling at this time?

-------------------------------

2. A student wants to test acceleration due to gravity, so he climbs to the top of a 900 ft. tall building and falls off the roof. 5 seconds later, Superman arrives at the scene and flies down to the bottom to catch him (Assume Superman's acceleration to be acceleration due to gravity).

A. What must Superman's Initial velocity be to catch the student immediately before the student would hit the ground?

B. What must be the height of the building so that even Superman cannot save him?

2007-10-09 08:30:58 · 2 answers · asked by Anonymous

how come i can grasp every math thing thrown at me but never can get physics??

2007-10-09 08:17:49 · 2 answers · asked by shadoyaj 4

"A 0.200 kg block is placed on a light vertical spring (k = 4.40 103 N/m) and pushed downward, compressing the spring 0.100 m. After the block is released, it leaves the spring and continues to travel upward. What height above the point of release will the block reach if air resistance is negligible?"

How do you do this, and what is your answer? Please break it down into steps. Thanks!

2007-10-09 07:46:09 · 2 answers · asked by justme 4

the tables edge. How fast should you roll the ball?

2007-10-09 07:22:21 · 1 answers · asked by Anonymous

A 12.4 g bullet is fired horizontally into a 98 g wooden block initially at rest on a horizontal surface. After impact, the block slides 7.5 m before coming to rest. If the coefficient of kinetic friction between block and surface is 0.650, what was the speed of the bullet immediately before impact?
The answer I have is 94.01, which is incorrect, though it's within 10% of the correct answer.
Any help would be appreciated!

2007-10-09 07:11:48 · 1 answers · asked by Bill 1

In the sucker of a cylinder there is 28 g Nitrogen in the temperature: t1= 0’ C. The sucker with section S= 100 cm2, through a drum system is connected to an object with weight 500 N. The cylinder is heated and it reaches the temperature: t2= 100’ C. Find the height in which the object goes down. The pressure of the atmosphere is 1 atm. (The weight of the sucker and the friction is not to be considered.)

2007-10-09 06:57:52 · 1 answers · asked by Crystal 3

It is well known that bullets fired at Superman simply bounce off his chest. Suppose that a gangster sprays Superman's chest with bullets of mass m = 2.9 g at a rate of R = 115 bullets/min. The speed of each bullet is v = 560 m/s. Suppose the bullets rebound with no change in speed. What is the average force exerted by the stream of bullets on Superman's chest?

2007-10-09 06:51:50 · 5 answers · asked by Anonymous

such as laser
flying cars micro chips
brain implants
time Travel
space travel
speed of light
speed of sound
all of these all true and technology only improve the last 50 yrs or so compare to 200yrs before that explain that

2007-10-09 06:44:50 · 7 answers · asked by SCANDOFONZnyc 2

Two objects, one moving north, one moving east, collide and stick together. If the eastbound object has three times the mass of and is initially moving half as fast as the northbound object, which of the indicated paths represents the most likely final motion of the pair? Justify your answer using the concept of linear momentum.

2007-10-09 06:15:21 · 2 answers · asked by bballchamp023 1

2007-10-09 06:11:28 · 12 answers · asked by max b 1

A cart slides down a frictionless inclined track to a circular loop of radius R = 13 m. In order for the cart to negotiate the loop safely, the normal force acting on the cart at the top of the loop, due to the track, must be at least equal to the cart's weight. (Note: This is different from the conditions needed to just negotiate the loop.)

a) What must be the minimum speed |vmin| of the cart at the top of the loop?

b) How high h above the top of the loop must the cart be released?

c) When the car is descending vertically in the loop (point (c) in the picture), what is its speed |v|?

d) At the bottom of the loop, on the flat part of the track, the cart must be stopped in a distance of d = 20 m. What retarding acceleration |a| is required?

2007-10-09 06:10:24 · 3 answers · asked by Anonymous

Two astronauts are each in a circular orbit around an unknown planet. Astronaut "A" is displaced 100 meters "vertically" from Astronaut "B" (that is, the two astronauts are 100 meters apart, on a line that intersects the planet's center).

How far apart will the astronauts be from one another, after they have completed one orbit?

(Surprisingly, the answer does not depend on the planet's mass or on the radius of the orbit. You may assume, however, that the radius of the orbit is much, much greater than 100 meters (and use any resulting mathematical approximations).)

2007-10-09 06:09:02 · 1 answers · asked by RickB 7

A motorcycle and rider have a combined mass of 250 kg and are traveling at a steady velocity of 17 m/sec. The force of wind resistance acting the motorcycle and rider at this speed is 150N.

a) What power must the motorcycle produce to sustain this velocity on level ground?


b) How power must the motorcycle produce to sustain this velocity on an upward incline of 39 degrees?


c) How much energy is produced by the motorcycle in 3 hours of driving on level ground?

2007-10-09 06:08:36 · 1 answers · asked by Anonymous

2007-10-09 06:07:43 · 1 answers · asked by MeMyself&I 1

In designing rotating space stations to provide for artificial-gravity environments, one of the constraints that must be considered is motion sickness. Studies have shown that the negative effects of motion sickness begin to appear when the rotational motion is faster than approximately 2.25 revolutions per minute. On the other hand, the magnitude of the centripetal acceleration at the astronauts' feet should equal the magnitude of the acceleration due to gravity on earth. Thus, to eliminate the difficulties with motion sickness, designers must choose the distance between the astronaut's feet and the axis about which the space station rotates to be greater than a certain minimum value. What is this minimum value?
I'm not even sure how to get started on this! Please help!

2007-10-09 05:28:59 · 2 answers · asked by NoV A 2