Physics - September 2007

the center of gravity of the box is elevated 3 m above the ground, the kinetic energy decreases 50 J. The only forces reacting upon the object is force R ( parallel to the incline) and the force of gravity. the incline is frictionless and g=9.841. calculate the magnitude of R

2007-09-16 16:40:16 · 1 answers · asked by wills 3

2007-09-16 16:31:13 · 7 answers · asked by stephanie 1

2007-09-16 16:18:42 · 8 answers · asked by Anonymous

An object with a known mass, say one kilogram, is moving in a direct line (say from West to East) from point 1 to point 2 with a known speed, say one meter per second. At 2 a force acts on the object. The force does not change the object's speed, but does change its direction of motion by 45 degrees (to the South East). Is it theoretically possible to calculate how strong the force was?

a) Yes, the strength of the force can be calculated (though I might not know how to do the calculation).

b) No, the force cannot be calculated by anyone.

2007-09-16 16:07:58 · 3 answers · asked by ? 6

A particle travels horizontally between two parallel walls separated by 18.4m. It moves toward the opposing wall at a constant rate of 7.7 m/s. It also has an acceleration in the direction parallel to the walls of 2.9 m/s2.

a. what will be its speed when it hits the opposing wall.

b. At what angle with the wall will the particle strike?

2007-09-16 15:40:51 · 1 answers · asked by glitterized_dreamz 1

For the ballistic missile aimed to achieve the maximum range of 16500 km, what is the maximum altitude reached in the trajectory?

2007-09-16 15:27:39 · 1 answers · asked by mathgeek 1

2007-09-16 15:25:54 · 2 answers · asked by Anonymous

Hi! I was wondering if anyone knew some good websites with dimensional analysis problems?

2007-09-16 14:59:02 · 2 answers · asked by Sgt. Pepper 2

A helicopter is flying horizontally at 8.3 m/s and an altitude of 20 m when a package of emergency medical supplies is ejected horizontally backward with a speed of 13 m/s relative to the helicopter. Ignoring air resistance, what is the horizontal distance between the package and the helicopter when the package hits the ground?

I've tried to work this problem about 10 different ways, but nothing seems to work...

2007-09-16 14:54:58 · 6 answers · asked by Doogin 3

A model of a helicopter rotor has four blades, each 3.60 m in length from the central shaft to the blade tip. The model is rotated in a wind tunnel at 580 rev/min.

(a) What is the linear speed of the blade tip, in m/s?
_________m/s
(b) What is the radial acceleration of the blade tip expressed as a multiple of the acceleration due to gravity, g?
_________ g

2007-09-16 14:54:39 · 2 answers · asked by Anonymous

A 4.90 g bullet leaves the muzzle of a rifle with a speed of 317 m/s. The expanding gases behind it exert what force on the bullet while it is traveling down the barrel of the rifle, 0.800 m long? Assume constant acceleration and negligible friction

2007-09-16 14:53:12 · 1 answers · asked by ひいらぎ 5

When a ball is at it's peak height (if you threw a ball in the air), is it at equilibrium?

2007-09-16 14:52:20 · 1 answers · asked by Shawn 1

a) Assuming a uniform acceleration, what is the velocity of the insect after it has accelerated through this short distance, and how long did it take to reach that velocity?
velocity 3.94 m/s
elapsed time 1.065*10^-3 s
How high would the insect jump if air resistance could be ignored? Note that the actual height obtained is about 0.7 m, so air resistance is important here.

2007-09-16 14:39:41 · 1 answers · asked by Mike 2

Two cranes are lifting identical steel beams at the time.One crane is putting out twice as much power as the other assuming friction is neglible, what can you conclude is happening to explain this difference?

2007-09-16 14:34:32 · 5 answers · asked by bklyn70 1

The driver of a truck slams on his brakes and skids to a stp through a distance d.
If the truck carried a diff load that its mass were quadrupled, what would be the skidding distance?
____*d

2007-09-16 14:14:21 · 2 answers · asked by ひいらぎ 5

A golf ball is struck with a five iron on level ground. It lands 105.0 m away 5.00 s later. What was the magnitude and direction of the initial velocity? (Neglect air resistance.)

____________ (m/s)
____________ * (Above the Horizontal)

2007-09-16 14:04:00 · 3 answers · asked by alimerzairan 1

A machine gun on the A-10 ground0 attack fighter aircraft fires 1300 rounds per minute, each of mass 1.4 kg, and attaining a speed of 800 m/s . Calculate the recoil experience by the aircraft.

2007-09-16 13:53:57 · 1 answers · asked by la_belle_creole_2000 1

for uniform motion, the line in a d-t graph is horizontal and in a v-t graph, the line is horizontal. I did an experiment where i have to push a cart and calculate the position and velocity of it for 1.0 second. However ,when I graphed the data, the line was not straight. What are some unavoidable sources of experimental error that might have cause my graph to differ from what was expected?

2007-09-16 13:45:54 · 1 answers · asked by Anonymous

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (see the drawing). Suppose that you loft the ball with an initial speed of v = 18.5 m/s, at an angle of = 46.0° above the horizontal. At this instant your opponent is 10.0 m away from the ball. He begins moving away from you 0.30 s later, hoping to reach the ball and hit it back at the moment that it is 2.10 m above its launch point. With what minimum average speed must he move? (Ignore the fact that he can stretch, so that his racket can reach the ball before he does.)

2007-09-16 13:42:12 · 3 answers · asked by yefimthegreat 1

2007-09-16 13:24:38 · 2 answers · asked by back2back 2

can ya'll help me with these here problems? it also says to leave the appropriatte number of significant figures in the answer. thanks.


a. 98512- 48.3
b. 3351.2- 40
c. 1000 x 48.3
d. 385/ 0.85
e. 1.008 / 0.500

2007-09-16 13:19:04 · 1 answers · asked by Anonymous

the plan start 20 degree N of East with speed 760 km/hr. the wind blow from West with speed 60 km/hr

a) which direction the plane end up flying
b) what is relative speed to ground

2007-09-16 13:16:32 · 1 answers · asked by jennifer 2

You are in a hot-air balloon that, relative to the ground, has a velocity of 6.2 m/s in a direction due east. You see a hawk moving directly away from the balloon in a direction due north. The speed of the hawk relative to you is 1.8 m/s. What are the magnitude and direction of the hawk's velocity relative to the ground?

2007-09-16 13:00:35 · 2 answers · asked by polly 1

2007-09-16 12:46:35 · 10 answers · asked by Anonymous

Why is the feild of view brighter under low power?

**NO DUMB ANSWERS PLEASE.

2007-09-16 12:45:00 · 1 answers · asked by Anonymous

2007-09-16 12:40:05 · 5 answers · asked by Anonymous

If a net force acts on an object, the object's velocity will change.
In order not to slow down, a car moving at a constant velocity needs a small net force applied.
During the collision of a car with a large truck, the truck exerts a greater force on the car than the car exerts on the truck.
The net force which acts on an object which remains at rest is zero.
If an object's speed does not change, no net force is acting on the object.
If two objects are under the influence of equal forces, they have the same acceleration.

i thought it was T, F, F, T, F, T But i seem to be \going wrong somewhere...help point me in the right directon please?

2007-09-16 12:32:45 · 2 answers · asked by Anonymous

2007-09-16 12:31:52 · 2 answers · asked by Anonymous

2007-09-16 12:11:46 · 4 answers · asked by kimberlinus 1

2007-09-16 11:58:16 · 1 answers · asked by kimberlinus 1