Question
Suppose a Chinook salmon needs to jump a waterfall that is 1.50 m high. If the fish starts from a distance 1.00 m from the base of the ledge over which the waterfall flows, find the x- and y-components of the initial velocity the salmon would need to just reach the ledge at the top of its trajectory. Can the fish make this jump? (Remember that a Chinook salmon can jump out of the water with a speed of 6.26 m/s.)
Could someone please help me with this question? Thanks alot
Could someone please help me with this question? Thanks alot
Answers
bobpursley
How much energy does it take to go 1.5m?
mgh=m*9.8*1.5= 14.7m joules
How much KE does the fish have initially?
1/2 m v^2= 1/2 m (6.26^2)=19.6m
Well, there is plenty of energy to go that high. So, will the fish go that high and still land 1m kupstream?
At the top , vvertical is zero. So how long will the fish take to fall that same distance?
vvertical= vverticalinitial-gt
0=6.26sinTheta-gt
This is the same time it takes to get to the top, so
t= 6.26sinTheta/g
How far does the fish travel hoizontally in that time?
1=6.26cosTheta*t
= 6.26costheta*6.26sinTheta/g
solvefor theta. Remember 2cosAsinA=sin2A
If you get an angle, the fish can do it.
mgh=m*9.8*1.5= 14.7m joules
How much KE does the fish have initially?
1/2 m v^2= 1/2 m (6.26^2)=19.6m
Well, there is plenty of energy to go that high. So, will the fish go that high and still land 1m kupstream?
At the top , vvertical is zero. So how long will the fish take to fall that same distance?
vvertical= vverticalinitial-gt
0=6.26sinTheta-gt
This is the same time it takes to get to the top, so
t= 6.26sinTheta/g
How far does the fish travel hoizontally in that time?
1=6.26cosTheta*t
= 6.26costheta*6.26sinTheta/g
solvefor theta. Remember 2cosAsinA=sin2A
If you get an angle, the fish can do it.