Physics - October 2007

A 75kg bobsled is pushed along a horizontal surface by 2 athletes. after the bobsled is pushed a distance of 4.5 m starting from rest, its speed is 6.0 m/s. find the magnitude of the net force on the bobsled. is the answer 300N?

*i think this problem has something to do with the work kinetic energy thm.

2007-10-30 15:54:26 · 5 answers · asked by Haya 1

Can someone explain to me why ionization energy increased as you move more electrons from anatom and does it follow a trend?

2007-10-30 14:52:14 · 1 answers · asked by Gamer G 4

What causes light to exit, with water, from a hole in the bottom of a bucket of water when a source of light, as a flashlight, is shone exactly normal or perpendicular to the surface of the water at the top of the bucket?

2007-10-30 14:28:37 · 3 answers · asked by lettishfetish4u 1

1. A stone is thrown, no air resistance. what is its vertical acceleration & its horizontal acceleration?
2. why an airplane moving through the air is not an example of projectile motion?

2007-10-30 14:28:02 · 2 answers · asked by Sunshine 2

a)the temperature increased
b)the temperature decreased
c) neither
I was told the answer is B, but I do not understand why. Can anyone explain?

2007-10-30 14:10:14 · 1 answers · asked by AnonymousOne 2

2007-10-30 13:49:01 · 6 answers · asked by Anonymous

If the Big Bang Theory is true, and all matter was condensed into one extremely small and dense area, then what was outside of the area where all matter existed?

2007-10-30 13:43:59 · 4 answers · asked by Anonymous

2007-10-30 13:29:31 · 2 answers · asked by harry b 1

2007-10-30 13:26:50 · 1 answers · asked by Kristijan R 1

Lets imagine that there was a small tube big enough for a human being to go fit that went form the N. Pole to the S. Pole, somehow surviving the core and not effect it. And someone jumps into it, would they fall and end up on the south pole, or would they hover in the middle, or what would happen (assuming he falls fast enough to go throw quickly yet still staying alive) I know its not possible, but was just wondering

2007-10-30 12:59:09 · 2 answers · asked by Anonymous

thanks!!!!

2007-10-30 12:56:30 · 2 answers · asked by Anonymous

Different mass crates are placed on top of springs of uncompressed length L_0 and stiffness k. The crates are released and the springs compress to a length L before bringing the crates back up to their original positions.

Rank the time required for the crates to return to their initial positions from largest to smallest.
Rank from largest to smallest.
1 )
k= 10 n/m
L= 5 cm
L_0= 10 cm

2)
k= 5 n/m
L= 10 cm
L_0= 20 cm

3)
k= 20 n/m
L= 5 cm
L_0= 15 cm

4)
k= 15 n/m
L= 10 cm
L_0= 15 cm

5)
k= 10 n/m
L= 5 cm
L_0= 20 cm

6)
k= 5 n/m
L= 5 cm
L_0= 10 cm

2007-10-30 12:42:08 · 1 answers · asked by Jarom J 1

I have no idea how to do this problem, please help!

Two objects of masses m and 4m are moving toward each other along the x-axis with the same initial speeds v0 = 40.0 m/s. The object with mass m is traveling to the left, and the object with mass 4m is traveling to the right. They undergo an elastic glancing collision such that mass m is moving downward after the collision at right angles from its initial direction.

(a) Find the final speeds of the two masses.

(b) What is the angle from its initial direction of motion at which the mass 4m is scattered?

2007-10-30 12:39:56 · 3 answers · asked by Brittany F 2

I don't understand this stuff at all. Please show some work.


Tarzan, whose mass is 85.0 kg, swings from a 3.50 m vine that is horizontal when he starts. At the bottom of his arc, he picks up 60.0 Jane in a perfectly inelastic collision. What is the height of the highest tree limb they can reach on their upward swing?

2007-10-30 12:37:08 · 2 answers · asked by Brittany F 2

In what direction and with what speed is the car moving? In other words, what is car’s velocity. Hint: this question requires input from Trigonometry for the right angle triangle.
Thus, the car was moving with the velocity of 38 m/s [E510N] (or, to the north of due east).

2007-10-30 12:35:10 · 1 answers · asked by navya 1

a baseball has mass .145. If the velocity of a pitched ball has a magnitude of 40.0 m/s and the batted ball's velocity is 65.0 m/s in the opposite direction, find the magnitude of the change in momentum of the ball.

2007-10-30 12:22:08 · 2 answers · asked by h k 2

A 76g particle moving with an initial speed of 150 m/s in the positive x direction strikes and sticks to an 80g particle moving with 72 m/s in the positive y direction.
How much kinetic energy is lost in this collision? Answer in units of J.

2007-10-30 12:20:29 · 1 answers · asked by MD12 2

It hooks up, then revereses, comes to a complete stop and and then starts to go forward. I have no idea....

2007-10-30 12:02:38 · 1 answers · asked by Anonymous

This is the situation:

A ball is attached to a rope which is spinning (vertically) at a constant rate. Now when you need to calculate the acceleration being exerted on the ball AT THE TOP, you subtract gravity from from the NORMAL force, because the gravity is pulling down and the Normal force us pushing up.

My question is: why is the Normal force pushing up. Shouldn't it be pushing in the same direction as gravity.

2007-10-30 11:59:37 · 2 answers · asked by Anonymous

question: a 2.1 x 10^3 kg car starts from rest at the top of a driveway that is sloped at an angle of 20.0 degrees with the horizontal. an average friction force of 4.0 x 10^3 N implodes the car's motion so that the car's speed at the bottom of the driveway is 3.8 m/s. What is the length of the driveway?

(question involves work-kinetic thm)

answer: 5.1m

how do you get this answer?

2007-10-30 11:57:37 · 1 answers · asked by Haya 1

how far away will be the ball after 1 hour?

Orbital period is 2 hours.
'Sideways' means the ball is thrown in direction perpendicualar to obital plane.

2007-10-30 11:37:16 · 1 answers · asked by Alexander 6

I have an object. I know the equation is a= Dv/Dt. My times are 2.8s and 4.0s. My velocities are 1.43 and 1.45. 10 points for giving the most thorough answer.

Also, show me how you did it please.

2007-10-30 11:33:27 · 1 answers · asked by Anonymous

g = 10 m/s/s
ignore air resistance

2007-10-30 11:25:37 · 10 answers · asked by Alexander 6

In a physics lab experiment, a spring clamped to the table is used to shoot a 45g ball at a 33 degrees angle. When the spring is compressed 17 cm, the call travels horizontally 6.0 m and lands 1.70 m below the point at which it left the spring. What is the spring constant?

2007-10-30 11:08:17 · 1 answers · asked by Anonymous

A balloon of mass M is floating motionless in
the air. A person of mass less than M is on
a rope ladder hanging from the balloon. The
person begins to climb the ladder at a uniform
speed v relative to the ground.
How does the balloon move relative to the
ground?
1. The balloon does not move.
2. Down with a speed less than v
3. Up with speed v
4. Down with speed v
5. Up with a speed less than v

2007-10-30 10:53:30 · 1 answers · asked by Anonymous

2007-10-30 09:57:44 · 3 answers · asked by 2Fast2Lose 1

Fool (meaning: infinite possibilities)
Lovers (meaning: infinite possibilities)
Hermit (meaning: limited possibilities)

What is probabilty P that infinite possibilities are ahead of us, and margin of error E of this prediction?

2007-10-30 09:54:23 · 3 answers · asked by Alexander 6

Try to keep your answers fairly non technical, I'm not a Physicist! I know that if two clocks are sync'd, and one is moved at a high rate of speed, and then brought back, the times will be different. What I want to know is, if a person leaves earth on a spaceship at near light speed, and returns 100 years later, will 100 years have passed for the person? Of course 100 years would have passed for the rest of the world, but would the person, who is aging slower, be able to do 100 years worth of work?

2007-10-30 09:52:09 · 18 answers · asked by tiak2 2

If you have 1 liter of liquid water under piston, and lower temperature to -1C, the water will freeze and expand. How much useful work could be done by the piston?

2007-10-30 09:43:57 · 1 answers · asked by Alexander 6

A rocket moves striaght upward, starting from rest with an acceleration of 29.4m/s^2. It runs out of fuel at the end of 4.00seconds and continues to coast upward, reaching a maximum height before falling back to Earth.

(a) Find the velocity the instant before the rocket crashes on the ground.





Not sure how to do this. Can anyone help walk me through it??
Thanks <3<3<3

2007-10-30 09:23:20 · 2 answers · asked by SurferGirl9 1