Physics - January 2007

A 18.7 kg block is dragged over a rough, hor-
izontal surface by a constant force of 130 N
acting at an angle of 29 above the horizon-
tal. The block is displaced 33.3 m, and the
coefficient of kinetic friction is 0.187.
The acceleration of gravity is 9.8 m/s2 :
Find the work done by the 130 N force.
Answer in units of J.

part2
Find the work done by the force of friction.
Answer in units of J.

part 3
If the block was originally at rest, determine
its final speed. Answer in units of m/s.

2007-01-11 09:40:06 · 1 answers · asked by kavita 1

2007-01-11 09:38:06 · 3 answers · asked by Rich 1

Okay, with a coeffeicient of friction of 1 the braking time from 50-0 is 0.71 seconds in a 1000 kg car. To get the braking time with a coefficient of 0.5 do I divide the 0.71 by 0.5? please help

2007-01-11 09:14:43 · 1 answers · asked by Anonymous

why?

2007-01-11 09:13:32 · 9 answers · asked by Anonymous

A person stands in stationary canoe and throws a 5.00-kg stone with a velocity of 8.00 m/s at an angle of 30 degrees above the horizontal. The person and canoe have a combined mass of 105 kg. Ignoring air resistance and effects of the water, find the horizontal recoil velocity (magnitude and direction) of the canoe.

2007-01-11 09:05:39 · 2 answers · asked by Someone 1

Considering the G-forces on the human body and a spacecraft traveling at the SPEED OF LIGHT, it would take a very long time to make a U TURN in outer space without the spacetravelers suffering any ill effects.

So...how long would it take (hours?...days?...weeks?...years ?) to safely make a U TURN in outer space?

2007-01-11 08:50:14 · 4 answers · asked by Anonymous

How much work can a 3.0 hp motor do in 0.60 h?

2007-01-11 08:38:49 · 2 answers · asked by gracelikerain 2

a) the light laser will be seen at speed 2c
b) the light will not be seen
c) the light will be seen at speed c
b) none of the above

2007-01-11 08:36:41 · 10 answers · asked by 8 3

What is the Average radius of the earths orbit with the sun.
Given Mass of sun - 2.00x10^30kg
Equations.. Fg = G x (m1xm2) / r^2
Fg = Fc
Fc = M x Centripetal Acceleration (which is noted as Ac)
Ac - v^2 / r

2007-01-11 08:35:24 · 3 answers · asked by UnK3 2

Three boys are trying to balance on a seesaw, which consists of a fulcrum rock, acting as a pivot at the center, and a very light board (which can be disregarded) of L = 3.74 m long.
Two boys are already on either end. One has a mass of m1 = 49.5 kg, and the other a mass of m2 = 32.0 kg. How far from the center should the third boy, whose mass is m3 = 22.2 kg, place himself so as to balance the seesaw?

How would you solve this problem? I have tried, but I am not getting the right answer.

2007-01-11 08:26:17 · 2 answers · asked by Anonymous

How many Seconds and millieseconds are in a year???

2007-01-11 07:58:43 · 4 answers · asked by Me 2

2007-01-11 07:21:40 · 2 answers · asked by LyDia W 1

Detailed question:

Two cars - Car A is going 100 km/h and Car B going 50 km/h

Both have a mass of 1000 kg

How fast is Car A going when Car B stops using breaks? Car A also presses on the breaks --- breaks are pressed at the same time.

Everything is a controlled variable except for the speed.

How do i figure this out using kinematics equations?

All I have is that the car's both have a mass of 1000kg and Car A is travelling at 100 km/h and car B is travelling at 50 km/h

2007-01-11 07:21:31 · 4 answers · asked by Anonymous

Two trains A and B are initially 100 miles apart facing each other on the same train track. Unfortunately the trains are headed toward each other, and each is going at a constant speed of 50 miles per hour. A superfly starts on the front of train A, flies to train B, immediately turns around and flies back to train A, etc. The fly zigzags this way back and forth at a speed of 200 miles per hour until the trains collide. At the last second (fortunately) our fly moves away from the collision. How many miles does the super fly travel until the trains collide? (its OK to neglect the length of the train).

2007-01-11 06:53:56 · 3 answers · asked by Angelo's Mommy 2

Is it important?

2007-01-11 06:48:29 · 4 answers · asked by Link 5

2007-01-11 06:26:52 · 6 answers · asked by jim 1

2007-01-11 06:20:22 · 9 answers · asked by Dr. Jan 2

At the annual turtle races, Poindexter, the previous year's winner, is trying to retain his title. As the race begins Poindexter starts off moving with a speed of 0.025 m/s. He retains this speed for 0.5 meters at which time he speeds up to 0.10 m/s. He continues at this rate for 0.75 meters. Tiring, he slows to 0.07 m/s and continues for another half of a meter. Applying all his concentration and effort for the last bit of the race he increases his speed to a swift 0.085 m/s. An exhausted Wood Turtle, Poindexter completes his two meter race beating his closest competitor by a nose.

In what amount time did Poindexter run the race?

2007-01-11 06:09:03 · 2 answers · asked by star wars freak 2

they say the speed of light is aprox.186,000 miles/sec.Lets say that the speed of light is exactly 186,000miles/sec.Why can't it be 186,001miles/sec. I'm familiar with E=mc2,and the speed of light is a constant,BUT, why can't the speed of light be faster?

2007-01-11 06:07:13 · 12 answers · asked by Anonymous

day??........Its just that now a days you hear about a lot of theories in physics and that, but as theories arise so do people who are against them.......so in the end which group can have the last word on whether a theory is plausible or not............ive seen that in the past they would all get together and discuss about physiscs......reknown physicist like einstein and bohm and all those others would go.....is that still going on??? and who goes there?

2007-01-11 06:02:30 · 2 answers · asked by feelingtherain 2

As I understand it, dark matter is presumed to be there because there needs to be more mass in the galaxy to hold it all together. And with black holes being hard to detect especially a supermassive one at the centre of the galaxy, could dark matter just be black holes?

2007-01-11 06:02:27 · 10 answers · asked by coolman9999uk 2

IPC Class -10th Grade/Using Holt Science Spectrum & in Chapter 7 Section 2. About Nuclear Fission and Fusion.

Please Help!

2007-01-11 05:37:15 · 2 answers · asked by Matt D 1

IPC Class -10th Grade/Using Holt Science Spectrum & in Chapter 7 Section 2. About Nuclear Fission and Fusion.

Please Help!

2007-01-11 05:35:36 · 3 answers · asked by Matt D 1

The answer is 141 m/s. The equation used is t=v2d/g. I have a quiz this evening, and I can't seem to figure out how they arrived at the answer using this equation. (the book does not show the equation in action). 5 points to the first person who can show me how this is worked.

2007-01-11 05:21:30 · 3 answers · asked by micropterushunt 2

i dont get it. the earth moves close to the sun, then after it goes around the back of it it goes further away from the sun. i thaught that the suns gravitational pull would pull it closer to the sun. so why does it go from being so close to the sun and escape its gravitational pull which brings it closer to the sun in the first place. i dont get it

2007-01-11 04:31:42 · 5 answers · asked by The Britt 1

link

http://answers.yahoo.com/question/index;_ylt=ApkLb0jcccfCJoBGZjv_IztIzKIX?qid=1005121101244

P.S. Does fire have mass? For example, could a campfire be supercooled and frozen....?

2007-01-11 04:30:49 · 7 answers · asked by Peter in La Jolla San Diego CA 4

2007-01-11 03:50:20 · 9 answers · asked by ana_is_a_cat 4

So, my friend and I recently watched a movie trailer about people commiting suicide by jumping off the Golden Gate Bridge.

We found that the distance between the bridge and the water is about 220ft.

He says that there is no way that anyone would be able to surive a fall into the water at such a height.

I say that its possible to survive such a fall if you perhaps entered the water properly and werent knocked unconscious.

Who is right? and why?

2007-01-11 03:29:07 · 6 answers · asked by xoil1321321432423 4

i do have a theory but dont have anyone to discuss wid, if anyone interested then plz ask me, plzzzz.

2007-01-11 03:25:25 · 11 answers · asked by da_frost_god 1

My dad told me about it. He said they used these things like on the fly to teleport a piece of paper. it was only 6 inches away from what it was. But still do you know what that is the start of??

2007-01-11 02:55:53 · 4 answers · asked by Anonymous