Physics - September 2007

2007-09-22 16:36:23 · 7 answers · asked by Anonymous

A second ball is thrown at an angle of 30 degrees with the horizontal. The acceleration of gravity is 9.8m/s/s. At what speed must the second ball be thrown so that is reaches the same height as the one thrown vertically? Answer in units of m/s.

2007-09-22 16:30:31 · 2 answers · asked by mira s 1

2007-09-22 16:25:36 · 2 answers · asked by Anonymous

A dockworker applies a constant horizontal force of 90.0 N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 13.0 m in a time 5.20 s.

2007-09-22 15:57:13 · 2 answers · asked by bg 1

it would be nice you if you could back up your findings and including your answer a definition of acceleration.

2007-09-22 15:23:22 · 1 answers · asked by kiwi 1

A projectile is shot from the edge of a cliff h = 185 m above ground level with an initial speed of v0 = 155 m/s at an angle of 37.0° with the horizontal, as shown in Fig. 3-35.

http://www.webassign.net/giancoli5/3_39alt.gif
Figure 3-35

(a) Determine the time taken by the projectile to hit point P at ground level.
s

(b) Determine the range X of the projectile as measured from the base of the cliff.
km

(c) At the instant just before the projectile hits point P, find the horizontal and the vertical components of its velocity. (Take up and to the right as positive directions.)
horizontal m/s
vertical m/s

(d) What is the the magnitude of the velocity?
m/s

(e) What is the angle made by the velocity vector with the horizontal?
° (below the horizontal)

(f) Find the maximum height above the cliff top reached by the projectile.
m

2007-09-22 15:04:18 · 1 answers · asked by oxblackout12 1

There's 12 HP, how do you express this power in SI system and report the numerical value in kilowatts.?

2007-09-22 15:01:59 · 5 answers · asked by shall_i 1

If a car rolls gently (v0 = 0) off a vertical cliff, how long does it take it to reach 80 km/h?
Answer in seconds

2007-09-22 14:51:55 · 2 answers · asked by John 1

How is it possible that the total amount of mobile charge in a capacitor is the same after charging as before charging.

2007-09-22 14:41:02 · 4 answers · asked by shall_i 1

2007-09-22 13:46:47 · 7 answers · asked by Anonymous

I'm taking honors physics this year, and I've come across a problem that I really don't understand.
Here's the question:

"A student throws a set of keys vertically upward to her sorority sister, who is in a window 4.00 m above. The keys are caught 1.50 s later by the sister's outstretched hand.
(a) With what initial velocity were the keys thrown?
(b) What was the velocity of the keys just before they were caught?"

Here is what I'm assuming from the problem:
(a) is asking initial velocity (v0)
(b) is asking final velocity (vf)
delta d is 4.00 m
delta t is 1.50 s
Average Velocity is 2 and 2/3 m/s (Because velocity = distance/time)


I can't for the life of me figure out how to find the initial and final velocities. Can someone please explin this to me?

Thanks!!!

2007-09-22 13:23:47 · 3 answers · asked by mew1033 2

2007-09-22 13:22:31 · 7 answers · asked by sed 1

5. In 1990, the women's record in bicycling was set by a Russian athlete. Starting at a certain speed, the bicyclist traveled 2 x 10^2 m. Suppose the initial velocity was 12 m/s and the acceleration was constant. If the final velocity was 25 m/s, what was the acceleration? How long did it take to travel this distance?

2007-09-22 13:19:18 · 1 answers · asked by KatieLC91 1

3. The polar bear is an excellent swimmer, and it spends a large part of its time in the water. Suppose a polar bear wants to swim from an iceberg to a place in shore where seals gather. The bear starts swimming at a velocity of 2.60 m/s. By the time it reaches the shore, its velocity has decreased to 2.20 m/s. If the polar bear's swim takes 9 minutes and it has a constant deceleration, what is the distance traveled by the polar bear?

4. A daredevil motorcycle rider pops a wheelie at a velocity of 8 m/s. He finds he needs to speed up to maintain this stuntm and so accelerates at 2 m/s^2 and travels 40 m during this acceleration.
a. What is the rider's velocity after the acceleration?
b. How much time did it take to travel this distance?

2007-09-22 13:18:07 · 2 answers · asked by KatieLC91 1

Physics question, I can't seem to get this problem, please help.?
Two forces, 381N at 8deg. & 307N at 25deg. are applied to a car in an effort to accelerate it.?
What is the magnitude of the resultant of
these two forces?

What is the direction of the resultant force (in re-
lation to forward, with counterclockwise con-
sidered positive)?????
within the
limits of -180deg to 180deg

Additional Details


655.52 was the answer for the first question... and so if 655.52 is the resultant force, what is the direction of deg?

2007-09-22 13:18:01 · 3 answers · asked by ? 1

A block of mass m = 2.7 kg is dropped from height h = 55 cm onto a spring of spring constant k = 1190 N/m (Fig. 8-38). Find the maximum distance the spring is compressed.

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter8Problem22.jpg

2007-09-22 13:13:31 · 1 answers · asked by James B 1

Because to see in the dark, your pupils (irises, or whatever) get bigger to allow in more light. But the clearest images are produced by pinhole cameras (where the hole is as small as possible).

So is our night vision actually inherently blurry because of the wider aperture? Or do our eyes focus it to normal anyway?

2007-09-22 13:12:04 · 2 answers · asked by a forest nymph 3

In the Figure, a horizontal force Fa of magnitude 22 N is applied to a 2.9 kg book as the book slides a distance d = 0.6 m up a frictionless ramp at angle θ = 30°. The book begins with zero kinetic energy. What is its speed at the end of the displacement?

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter7Problem20GO.jpg

2007-09-22 13:11:02 · 3 answers · asked by James B 1

A loaded penguin sled weighing 87 N rests on a plane inclined at angle θ = 22° to the horizontal (Fig. 6-28). Between the sled and the plane, the coefficient of static friction is 0.26, and the coefficient of kinetic friction is 0.18. (a) What is the minimum magnitude of the force , parallel to the plane, that will prevent the sled from slipping down the plane? (b) What is the minimum magnitude F that will start the sled moving up the plane? (c) What value of F is required to move the sled up the plane at constant velocity?

http://i225.photobucket.com/albums/dd182/jameslotobond/Chapter6Problem20.jpg

2007-09-22 13:07:27 · 2 answers · asked by James B 1

A broad jumper begins his jump at an angle of 22.0 degrees from the horizontal. At the middle of the jump he reaches a height of 70.0 cm. What is the horizontal velocity?

2007-09-22 13:06:55 · 2 answers · asked by Anonymous

A common flea is recorded to have jumped as high as 21 cm. Assuming that the jump is entirely in the vertical direction and that air resistance is insignificant, calculate the time it takes the flea to reach a height of 7.0 cm.

the answer is 0.04 s. i know how to get it, but i don't get why.
so i plugged it into that equation:
delta y = (initial velocity)(delta T) + (0.5)(acceleration)(time-squared)

0.07 = 0 + (0.5)(9.81)(time-squared)
t=0.12

so i divided 0.12 by 3. and i got 0.04 seconds.
why do you divide by 3? 7 cm is already a third of the highest jump of the common flea. wasn't i calculating the 7.0 cm jump time? not the 21 cm one?

or did i just completely fail at this problem?
help, thank you.

2007-09-22 13:05:15 · 1 answers · asked by Anonymous

A train pulls away from a station witha constant acceleration of .4m/s^2. A passenger arrives at at point next to the track 6s after the end of the train has passed the very same point. What is the slowest constant speed at which she can run and still catch the train?

2007-09-22 12:45:46 · 1 answers · asked by Anonymous

2007-09-22 12:36:57 · 3 answers · asked by Anonymous

Calculations done on page 253 of information provided by Maharishi Mahesh Yogi in book on Bhagavad -Gita.

2007-09-22 12:31:19 · 4 answers · asked by Washington 2

My question is almost the same as the question you see at this link, http://www.licil.org/Tucker/math/physics3.htm (#24-2 Electric Field),

The only differences are the E Field now piercing the Guassian cube is now E=4.0i-3.0(y^2+2.0)j, and find the electric flux through the top face, bottom face, left face, back face, and the net electric flux through the cube.

Just like always SHOW ME AS MUCH WORK AS POSSIBLE, and I have answer I just want to see if it is right, so PLEASE LEAVE AN ANSWER!

2007-09-22 12:19:17 · 1 answers · asked by Usef L 1

2007-09-22 12:15:23 · 3 answers · asked by Anonymous

Which statement below is false?

A. The wavelength of light is the distance between two corresponding points in the wave pattern.
B. The frequency of light increases as wavelength decreases.
C. The higher the frequency of light, the greater its energy.
D. The frequency of light is the number of waves that pass a given point in a second.
E. The higher the frequency of light, the longer the wavelength.

2007-09-22 11:34:13 · 6 answers · asked by desigoddess217 1

A van accelerates down a hill, going from rest to 30.0 m/s in 7.10 s. During the acceleration, a toy (m = 0.350 kg) hangs by a string from the van's ceiling. The acceleration is such that the string remains perpendicular to the ceiling.

Determine the angle of incline of the hill that the car is going down, and the tension of the string.

Thanks much!

2007-09-22 11:32:04 · 1 answers · asked by Bill 1

This mechanics problem is thoroughly kicking my ***. I would appreciate any help - preferably if you could take me step through step through how to solve it...

Two objects with masses of 2.00 kg and 5.00 kg are connected by a light string that passes over a frictionless pulley.
Determine the tension in the string in Newtons.
Determine the acceleration of each object.
(c) Determine the distance each object will move in the first second of motion if both objects start from rest.

Thanks much!

2007-09-22 11:28:56 · 1 answers · asked by Bill 1

This mechanics problem is thoroughly kicking my ***. I would appreciate any help - preferably if you could take me step through step through how to solve it...

Two objects with masses of 2.00 kg and 5.00 kg are connected by a light string that passes over a frictionless pulley.
Determine the tension in the string in Newtons.
Determine the acceleration of each object.
(c) Determine the distance each object will move in the first second of motion if both objects start from rest.

Thanks much!

2007-09-22 11:27:56 · 2 answers · asked by Bill 1