Recent content by apope

whether there is friction or not isn't important.. you want to know if you can apply a force forward moving the shopping cart, the magnitude of the force to overcome friction isn't important.. unless you tell us the strength of the person in the cart, the coefficient of friction and the weight...

work is the force x distance. the kinematics equation relating acceleration to distance is a = vf^2 - vi^2/2d F = ma so... F = mvf^2 - mvi^2/2d multiply this by the distance.. and the change in kinetic energy is mvf^2-mvi^2/2 soo.. 1/2mv^2 = change in kinetic energy.

so it's like.. you need to know the force being applied.. just like you can't know how fast a certain force can accelerate something without knowing its mass?

1 Joule = 1N x 1m which means 1 Joule = 1kg x 1m/s^2 x 1m but can it also mean that the object accelerates at 0.5m/s^2 and travels 2m? The mass is constant, so if it is given 1J of energy how do you know the factors of the acceleration and the distance?

i think bart would skateboard off the Earth and gravity would pull him into orbit.

so we're talking about charges.. like electromagnetic forces or gravitational forces? what laws don't work together and why not??

Where exactly do the laws of relativity and quantum mechanics disagree?

so basically... the time it takes for the light to reach the mirror and come back relative to the astronaut in the ship is shorter than the time i observe it to happen? does this not mean that the event occurs twice? sorry if it's a stupid question

im beginning to understand.. but can someone give me another example of time dilation that could help me out.

that's exactly what's happening in this example... i didn't realize the second beam was shot on an angle like that, i thought they were both shot up in straight lines. but then, shouldn't it take longer for the second beam to hit the mirror even if the ship weren't moving since its vertical...

my textbook shows me an example where an astronaut is in a spaceship beside 2 parallel mirrors with a beam of light coming from the bottom, reflecting off the top and coming back to the bottom. It says that the light has to travel farther if the spaceship is moving because it must travel the...

i understand the centripetal force concept.. but I'm thinking in more of like yo-yo terms.. like i can have a rock on a string and pull it up to my hand you know? and also if you spin a rock on a string.. you can't get it done just by pulling on it.. you have to like use your fingers and wrist...

why does an electron orbit a positive nucleus.. if it is attracted to it should'nt it take a straight path and like stick to it? what's keeping it from doing that? same with planets.

I'm doing a project on dark matter and I've found some good information but I still haven't found any related mathematical equations.. are there any not to complicated ones i can relate to it??