Physics - November 2007

A race car starts from rest on a circular track of radius 492 m. The car's speed increases at the constant rate of 0.690 m/s2. At the point where the magnitudes of the centripetal and tangential accelerations are equal, find the following.
(a) the speed of the race car
(b) the distance traveled
(c) the elapsed time

2007-11-06 11:47:26 · 1 answers · asked by Anonymous

2007-11-06 11:41:00 · 4 answers · asked by Anonymous

I am building an air cannon for my science fair project. The question is "What is the best possible angle for the most distance when firing a projectile?". I thought it might be 45 degrees (because 45 degrees is the perfect balance between straight up and straight forward) but I have been told it isn't 45 degrees. I thought about it and i have come to the conclusion that it must be a lower angle because of gravity and air resistance. I would also like any websites addressing this topic.

2007-11-06 11:24:39 · 4 answers · asked by pianoman2011 1

..or is it a scalar? Quite the conundrum lol. Thanx in advance :)

2007-11-06 11:19:35 · 5 answers · asked by Anonymous

2007-11-06 11:18:18 · 1 answers · asked by Anonymous

I understand what the following question is trying to say, but I'm not sure how to explain it.

You are helping a friend move furniture. The friend asks you to stand inside the back of a pickup truck to hold a piano because there is no rope available to tie it to the truck. Explain why you should refuse this request. Your answer should show that you understand the reasoning used by Galileo and Newton.

Words such as inertia, mass, etc. should be used. Please help me explain this. Thanks :)

2007-11-06 11:11:57 · 1 answers · asked by Anonymous

Please help me with these 2 questions:
Calculate the resultant velocity (diagonal) of a pair of 100 km/h velocities at right angles to each other

If a 14-unit vector make an angle of 45 degrees with the horizontal, what are its horizontal and vertical components ?

2007-11-06 11:08:24 · 3 answers · asked by missybitsy 1

A baseball is hit off a 1 meter high tee at an angle of degrees and at a speed of m/s. How far to the nearest tenth of a meter does it travel horizontally?

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2
A golf ball is chipped at an angle of degrees and with a speed of m/s how far does it travel to the nearest tenth of a meter?

A monkey swings on a vine and at the bottom of the swing while moving horizontally lets go of the vine aiming for another vine meters away horizontally and whose bottom is meters below the monkey. How fast must the monkey be moving to the nearest tenth of a m/s in order that he just catches the bottom of the vine?

2007-11-06 10:43:24 · 1 answers · asked by Anonymous

A 20.0 kg box rests on a table. What is the weight of the box and the normal force acting on it? A 10.0 kg box is placed on top of the 20.0 kg box. Determine the normal force that the table exerts on the 20.0 kg box and the normal force that the 20.0 kg box exerts on the 10.0 kg box.

Please show/explain work clearly.

2007-11-06 10:39:11 · 1 answers · asked by Kantilal P 1

An electric motor draws 1/2 horsepower while it is operating. The motor is used continuously for 12 hours a day to run an evaporative cooler. Assume that electrical energy costs 11 cents per kilowatt.hour.

2007-11-06 09:55:11 · 1 answers · asked by labelapark 6

A piano with a mass of 250 kg is pulled up a ramp lying on the stairway of a house. The ramp is 6 meters long and the coefficient of sliding friction is .180. If the plank makes an angle of 42 degrees with the horizontal, find:

a. the force of friction (N)
b. the force required to pull the piano (N)
c. the work done in pulling it up to the top (J)
d. the potential energy acquired

2007-11-06 09:29:24 · 1 answers · asked by labelapark 6

A 17000 kg freight car is rolling along a track at 1.7 m/s.

Calculate the time needed for a force of 1890 N to stop the car. Answer in units of s.

2007-11-06 09:26:32 · 1 answers · asked by lilprincess_2good4u 1

A small WWI biplane traveling at 120 km/hr in a straight and level flight 160 meters above the ground drops a small contact bomb. Find:

(a) the time it takes for the bomb to fall to the ground
(b) the horizontal distance traveled by the bomb after is it released
(c) the vertical speed acquired by the bomb as it just touches the ground
(d) the total speed of impact

2007-11-06 09:22:51 · 2 answers · asked by labelapark 6

Question 1 - Please explain in steps if possible

A bicycle wheel is 30 inches in diameter.
a. To the nearest revolution, how many times will the wheel turn if the bicycle is ridden for 3 miles?
b. Suppose the wheel turns at a constant rate of 2.75 revolutions per second. What is the linear speed in miles per hour of a point on the tire?

Question 2

Low Earth orbiting (LEO) satellites orbit between 200 and 500 miles above Earth. In order to keep the satellites at a constant distance from Earth, they must maintain a speed of 17,000 miles per hour. Assume Earth's radius is 3960 miles.

a. Find the angular velocity needed to maintain a LEO satellite at 200 miles above Earth.
b. How far above Earth is a LEO with angular velocity of 4 radians per hour?
c. Describe the angular velocity of any LEO satellite.

2007-11-06 09:20:06 · 1 answers · asked by Anonymous

to stay in it's place.


why?

2007-11-06 09:04:38 · 1 answers · asked by Anonymous

is it worse, the same of better? assume that other factors such as speed and tires are the same

please explain, i'm totally lost!

2007-11-06 09:03:50 · 2 answers · asked by Anonymous

The rod is 4m long, with a weight Fg. One end, Point B, is supported by a cable from the wall. The other end, Point A, rests against a wall with μ s = 0.5. The angle between the cable and Point B is 37 degrees. Basically, the question is asking how far out from the wall can an extra weight, Fg, same as the weight of the rod, be placed without causing the rod to slip at Point A. (Diagram looks smiliar to a triangle). No actual weights are given.

2007-11-06 09:01:04 · 1 answers · asked by Anonymous

A ferrari accelerates from 0 to 100 km/h in 4.8 sec. What force (in newtons) does a passenger of mass 68 kg experience during acceleration?

2007-11-06 09:00:53 · 2 answers · asked by Paul T 1

What is the efficiancy?

Please show me how to do it. I was absent and my teacher precisely doesn't teach us how to do anything.

I know Efficiency = (W out / W in) * 100% but how do you get W out and W in? :O

2007-11-06 08:58:08 · 1 answers · asked by xuchihasakurax 2

A 50.0 kg archer, standing on frictionless ice, shoots a 200 g arrow at a speed of 200 m/s. What is the recoil speed of the archer?

2007-11-06 08:51:02 · 1 answers · asked by Paul T 1

is it worse, the same of better? assume that other factors such as speed and tires are the same

please explain, i'm totally lost!

2007-11-06 08:43:08 · 3 answers · asked by Anonymous

that same curve on earth?

please explain this to me; i don't get it.

2007-11-06 08:41:06 · 2 answers · asked by Anonymous

two window washers, bob and joe, are on a 3m long, 395N scaffold supported bt two cables attached to its ends. bob weighs 800N and stands 1m from the left end. two meters from the left end is 500 N washer equipment. joe is .5m from the right end and weighs 990N. given that the scaffold is in rotational and transitional equilibrium, what are the forces on each cable

2007-11-06 08:39:30 · 2 answers · asked by Dana 1

two sphere have equal densities and are subject only to their mutual gravitational attraction. Which the following quantities must have the same magnitude for both spheres.
a) acceleration
b) velocity
c) kinetic Energy
d) Displacement from the center of mass
e) Gravitational force
I think it is e

An ice skater is in a spin with his arms outstretched. If he pulls in his arms, what happens to his rotational kinetic energy?
a) increase
b) decrease
c) remains constant but non-zero
d) remains zero
i think it is a

2007-11-06 08:26:26 · 1 answers · asked by ken 2

2007-11-06 08:12:06 · 3 answers · asked by Alexander 6

A uniform 45 pound gate, 3 ft. wide and 5 ft. high is supported by two hinges. Each hinge is located 6 in. from the top and bottom of the gate. What force, in pounds, acting perpendicular to the upper hinge must the upper hinge supply to support the gate? I have been working on this problem with no success and it's due tomorrow! Help! Please explain fully how to arrive at the answer.

2007-11-06 07:57:54 · 1 answers · asked by kitty 3

hey if anyone can help me with these problems, id greatly appreciate it

1.Two 1.5 Kg balls move away from each other, one traveling 5 m/s to the right, the other 5 m/s to the left. What is the magnitude of the total momentum of the system? in terms of Kg X m/s?
2. Two 1300 kg cars drive east: the first moving at 30 m/s, the second at 45 m/s. What is the magnitude of the total momentum of the system? in terms of Kg X m/s?
3. What is the momentum of a two particle system composed of a 1300 kg car moving east at 60 m/s and a second 1300 kg car moving west at 15 m/s. Let east be the positive direction. Answer in terms of KG X m/s

2007-11-06 07:53:17 · 2 answers · asked by Anonymous

on my problem it just gives the weight and time but not the force and distance and tells me to find the work ...........how do i find it??

2007-11-06 07:48:08 · 1 answers · asked by ~You are junk~ 2

If balls were lying on a chart they would be positioned at

Ball 1 (-2.5 m, -1.5 m) mass = 1 kg (1 & 2 are 3 m apart)
Ball 2 (-2.5 m, 1.5 m) mass = 2 kg (2 & 3 are 5 m apart)
Ball 3 (1.5 m, 2.5 m) mass = 3 kg (3 & 4 are 3 m apart)
Ball 4 (-1.5 m, 2.5 m) mass = 4 kg (4 & 1 are 5 m apart)

rectangular system is centered on chart with Origin being (0,0)

What is the moment of inertia of the x axis?
What is the moment of inertia of the y axis?
What is the moment of inertia of the z axis? (the axis through the origin and perpendicular to the page

2007-11-06 07:41:28 · 1 answers · asked by Pascal 4

If frictional forces do −1.01×104 of work on her as she descends, how fast is she going at the bottom of the slope?
Take free fall acceleration to be = 9.80 .
Now moving horizontally, the skier crosses a patch of soft snow, where the coefficient of friction is = 0.250. If the patch is of width 70.0 and the average force of air resistance on the skier is 180 , how fast is she going after crossing the patch?

After crossing the patch of soft snow, the skier hits a snowdrift and penetrates a distance 2.30 into it before coming to a stop. What is the average force exerted on her by the snowdrift as it stops her?

2007-11-06 07:20:12 · 1 answers · asked by elturi2k@sbcglobal.net 1