Hi David
It was all going great until your vertical consideration of motion !
Quite simply, if the ball is going to be landing BELOW the LEVEL of projection, its OVERALL displacement is negative ! In my other example, displacement was positive because the ball was horizontally projected...
Cristo I'm not criticising anybody's work here; I made no reference to your method being incorrect in any way. If you don't understand collisions then consult someone who does, please don't say my work is "incorrect" when it isn't, you're just making it difficult for students who need help...
okay if you're making the assumption that it's a perfectly elastic collision, note that this implies that the coefficient of restitution between the particles would equal 1. Hence the particles will have the same final speed as their initial, with their direction of motion reversed. However...
The collision is not perfectly elastic, it is "elastic". So energy is not conserved. And besides, perfect elasticity is an unrealistic assumption, especially where two "objects" are concerned. You need more information.
the answer in the textbook is 100% correct
Impulse is never negative, and the magnitude of the force would be 11012.5 N
remember I = mu - mv in this case
answer to the football kicked on a slope question
okay this is a straightforward question (you don't need to solve for time anywhere in this !)
for my equations I am using the following notations
a = acceleration u = initial velocity v = final velocity s = displacement
t = time...
hi
Momentum = mv (mass x velocity)
Potential energy = mg∆h (mass x acceleration due to gravity x ∆ height)
Kinetic energy = 1/2 mv^2 ( 1/2 x mass x velocity squared)
work done = force x distance traveled in the direction of the force
since work done is energy
it follows...
solution to the "particle being projected from 265m cliff" question
If I interpreted it correctly this is a very straightforward question
let s = displacement a = acceleration u = initial velocity
and v = final velocity
By considering the vertical motion of the particle from...