Recent content by Luca 123

Homework Statement A mass m1, with initial velocity u, collides elastically with mass m2, which is initially at rest. After collision, m1 deflects by angle θ. Find the maximum value of θ. The answer given is θmax=acos(sqrt(1-(m1/m2)^2)). Does this mean that the maximum angle cannot exist if...

Then how exactly did we derive them? Is there some links available showing the derivation? Or if you are willing to, maybe you can show me how?

I know that Keplar's First law is true, but it doesn't occur to me why do stars orbit the center of gravity. Is there a proof for that, or a way for me to visualise why? Also, to measure the eccentricity of the orbit, e^2=1+(2E(L^2))/(GM(m^2)). How did they derive this equation?

Homework Statement A frog of mass m jumps from the edge of a plank of mass M of length L to the other edge. The plank is on water and is free to move, assume no friction whatsoever. What is the minimum value of the speed of the frog ? Homework Equations Conservation of momentum and energy Some...

I'm confused. Isn't the Earth rotating on its own axis, and we are rotating along with it? Doesn't gravity act as the centripetal force? The Earth itself is a rotating frame, so the laws of ratational motion should apply(?)

However, in this case, wouldn't I feel weightless? Do I feel weight(i.e. normal force=/=0) because the Earth isn't perfectly spherical?

Also, what if we assume that the Earth is perfectly spherical, and since I'm standing still relative to the Earth, wouldn't the centrifugal force=GMm/r^2 ?

So in this case, what would the centrifugal force be? I have normal force=mg=GMm/r^2, but the centrifugal force can't be zero right? So what went wrong in my calculations?

We know that the Earth is rotating, and its gravitational force is the centripetal force. So if I'm standing on the Earth, I'll feel 3 forces: Gravitational force, normal force and centrifugal force. However, the magnitude of the centrifugal force is equal to the gravitational force, so wouldn't...

Let's say there is a cart with a pendulum inside it. The cart then starts accelerating, while an observer on the ground remain still. I was told that the observer, standing still, would not observe any fictitious forces on the pendulum, so how does he explain the pendulum swinging backwards?

Thx a lot! I understand now :)

Consider 2 ends of a massless spring, where end A is attached to a block, and end B is being pulled by a force with magnitude F. The spring is streched X m.The magnitude of thd restoring force of the spring at end B, F(re)=/=F.What is the magnitude of the force the spring exerts on the block, at...

F is a vector. It is the force exerted.

So if I have a block of mass connected to a spring with spring constant k. If I pull the spring with force F, what is the force that is pulling the block? Is it F or the restoring force of the spring? I think it should be the restoring force of the spring, but if it is F, why is it so?

Thanks, I solved the problem:)