Physics - September 2007

At the earth surface a projectile is launched straigh up at the speed of 10 km/s. TO what height will it rise ? Ignore air resistance

Thanks

2007-09-17 20:19:01 · 4 answers · asked by Anonymous

2007-09-17 19:46:27 · 2 answers · asked by dragon 2

A piece of Styrofoam maving a mass m carries a net charge of -q and floats above the center of a very large horizontal sheet of plastic that has a uniform charge density on its surface. What is the charge per unit area on the plastic sheet?

The force of gravity must be equal to the electric force for the Styrofoam to "float"..

Fg = Fe
mg = qE

I'm at a loss as to what to do next. I think there's a relationship that ties the field strength to the charge density, but I have no clue what it is. Some help?

2007-09-17 18:59:27 · 2 answers · asked by darkhydra21 3

please help with my homework. need kind explaination.
A person threw a ball vertically up. 3.0 seconds later it hit the ground. What is initial speed when he threw the ball and what is total distance. I need the formular also please. thank you

2007-09-17 17:07:36 · 1 answers · asked by junheo01 1

At the Earth's surface, a projectile is launched straight up at a speed of 10.0km/s. To what height will it rise? ignore air resistance.

i know that you have to take into consideration the gravitational force constant, as the projectile has such a high inital velocity so that the acceleration due to gravity wont b 9.8 ms-2

2007-09-17 16:28:35 · 1 answers · asked by two_quic 1

A car that weighs 12700.0 N is initially moving at a speed of 35.0 km/hr when the brakes are applied and the car is brought to a stop in 4.8 s. Find the magnitude of the force that stops the car, assuming it is constant.
I found the magnitude to be 2.62 X 10^3 N and now it's asking for the distance the car moved?

2007-09-17 16:02:46 · 1 answers · asked by Anonymous

A worker drops a wrench from the top of a tower 80 m tall. What is the velocity when the wrench strikes the ground?

2007-09-17 16:02:33 · 2 answers · asked by strawberry 7 2

An object has an initial velocity of magnitude of 15 m/s to 30° north of east. It is subjected to the forces:
F(1) = 20 N(newtons), 40° south of east.
F(2) = 80 N, 20° west of north.

Motion is detected by adding the force vectors and finding the Net Force. The Accel is the net force vector divided by the objects mass (2 kg).
After 4 seconds find:
A. magnitude of displacement. |x|
B. direction of displacement.
C. magnitude of velocity.
D. direction of velocity.

2007-09-17 15:46:57 · 1 answers · asked by johnnyboy 2

A ball is thrown vertically upward (assumed to be the positive direction) with a speed of 18.0 m/s from a height of 4.0 m.
(a) How high does the ball rise from its original position?
m

2007-09-17 15:41:40 · 3 answers · asked by Anonymous

A pedestrian moves 4.4 km east and then 7.8 km north.
Find the magnitude of the resultant displacement vector. Answer in units of km

Part 2 of the question
What is the direction of the displacement vector (using the counter-clockwise angular direction to be positive, within the limits of -180° to +180°)? Answer in units of ° .

can you please explain how you got the answer, thanks best answer 10 points!

2007-09-17 15:41:39 · 1 answers · asked by Spoken_Truth 3

k is km/h/s an acceptable unit to measure acceleration???? That's all i need to know

2007-09-17 15:30:24 · 5 answers · asked by Anomaly 4

When chasing a hare along a flat stretch of ground, a greyhound leaps into the air at a speed of 12.7 m/s, at an angle of 25° above the horizontal.
(a) What is the range of his leap?
___m
(b) For how much time is he in the air?
___s

2007-09-17 15:14:48 · 3 answers · asked by Antonio E 1

A particle leaves its initial position X0 at time t = 0,moving in the positive x direction with speed V0 but undergoing acceleration of magnitude a in the negative x direction.Find expression for a) the timw when it returns to the position X0 and b) its speed when pass that point

2007-09-17 15:11:49 · 3 answers · asked by M R 1

A red car moving at 44.7 mph passes a blue car moving at 30.7 mph. (Use 1609 meters = 1 mile when converting to meters/second.) Seeing a stopped car in his lane up ahead, the driver of the red car applies the brakes just as he passes the blue car which causes the red car to slow down to a stop by losing 4.36 m/s every second.

(a) How much time (in seconds) passes before the two cars are side-by-side once again?
s




(b) When the cars are finally side-by-side, how do their average speeds compare for the time you calculated above? Please explain fully.

2007-09-17 15:09:07 · 2 answers · asked by ags101 2

i am confused, Please help
thanks

2007-09-17 15:08:36 · 4 answers · asked by Anonymous

When chasing a hare along a flat stretch of ground, a greyhound leaps into the air at a speed of 12.7 m/s, at an angle of 25° above the horizontal.
(a) What is the range of his leap?
____m
(b) For how much time is he in the air?
_____s

2007-09-17 15:05:22 · 1 answers · asked by Antonio E 1

in other words, what does g equal? is it something like g=1/2*v*t^2 or something???

2007-09-17 14:49:30 · 4 answers · asked by Anonymous

we know that there are two types of electrons, free electrons and in bound, i wanted to know whether they die or destruct or not?

2007-09-17 14:37:19 · 3 answers · asked by mina1828 1

A diver springs upward from a board that is three meters above the water. At the instant she contacts the water her speed is 9.10 m/s and her body makes an angle of 73.0° with respect to the horizontal surface of the water. Determine her initial velocity, both magnitude and direction.
___m/s (magnitude)
____° (direction)

2007-09-17 14:34:52 · 2 answers · asked by Marianna E 1

How could you determind the volume of an object that floats?

2007-09-17 14:20:51 · 1 answers · asked by Anonymous

When chasing a hare along a flat stretch of ground, a greyhound leaps into the air at a speed of 12.7 m/s, at an angle of 25° above the horizontal.
(a) What is the range of his leap?
___m
(b) For how much time is he in the air?
___s

2007-09-17 14:15:15 · 1 answers · asked by Marianna E 1

how do you find the dsplacement under a curve (parabola) in the velocity time graph?

2007-09-17 14:09:20 · 1 answers · asked by Anonymous

How will I set this problem up? 30cm/10g.

2007-09-17 14:05:32 · 3 answers · asked by diiA b. 1

A rock climber throws a small first aid kit to another climber who is higher up the mountain. The initial velocity of the kit is 24 m/s at an angle of 52° above the horizontal. At the instant when the kit is caught, it is traveling horizontally, so its vertical speed is zero. What is the vertical height between the two climbers?
m

2007-09-17 14:01:10 · 2 answers · asked by Marianna E 1

2007-09-17 13:52:48 · 5 answers · asked by To-the-Stars 4

When chasing a hare along a flat stretch of ground, a greyhound leaps into the air at a speed of 12.7 m/s, at an angle of 25° above the horizontal.
(a) What is the range of his leap?
____ m
(b) For how much time is he in the air?
____s

2007-09-17 13:43:37 · 1 answers · asked by Santina E 1

2007-09-17 13:40:02 · 4 answers · asked by diiA b. 1

2007-09-17 13:25:50 · 10 answers · asked by Mary M 1

A train moving with a constant velocity travels 180 m north in 12 s and an undetermined distance to the west. The speed of the train is 22 m/s.

How far west has the train traveled in this time?

2007-09-17 13:24:37 · 2 answers · asked by alimerzairan 1

An infinite sheet of charge, oriented perpendicular to the x-axis, passes through x = 0. It has area density s1 = -4 µC/m2. A thick, infinite conducting slab, also oriented perpendicular to the x-axis, occupies the region between x = a and x = b, where a = 2 cm and b = 3 cm. The conducting slab has a net charge per unit area of s2 = 6 µC/m2.

(a) Calculate the net x-component of the electric field at the following positions:

At x = -1 cm
At x = 1 cm:
At x = 6 cm

(b) Calculate the surface charge densities on the left-hand (sa) and right-hand (sb) faces of the conducting slab.

2007-09-17 13:23:15 · 1 answers · asked by Anonymous