Please help me understand;

a) so the eagle is flying horizontally in this problem with total mass of (itself + rabbit) = (5.0 + 1.5) = 6.5 kg

because of gravity, their combined weight is actually pulling the eagle down

he is flying horizontally so to do this he has to overcome the weight that is pulling him down

(this is a simplified problem because he is flying horizontally. lift force is actually perpendicular to the direction of the air going around his wings. if he were flying at an angle we would have to take components using trig. but since he is horizontal, all the lift force is simply opposing the weight pulling down)

lift force up = weight pulling down
weight = mass * gravitational acceleration
= 6.5 [kg] * 9.8 [m/s2] = 63.7 N

e: word

This post was edited by Squaunch on Mar 9 2018 12:19pm

b ) ii)

picture of whats happening

when he is landing on the rock, he exerts a downward force

but since the rock is on an angle, there is a component that is normal to the rock (the blue A)
and there is a component tangent/parallel to the rock (the green O)

to not slide, the rock needs to apply a friction force to oppose the green O


friction force = green O
by trigonometry,
sin(30 deg) = opposite/hypotenuse
= (green O) / 87
then (green O) = 87 x sin(30 deg) = 87 * 0.5 = 43.5 N = friction force

e: typing b ) is cool face
e2: thought this was b ) i) but its actually b ) ii)

This post was edited by Squaunch on Mar 9 2018 12:34pm

b ) i )
once the eagle has landed and is standing on the rock, there is downward force of their combined weight (Rabbit and eagle)
we solved this in a), its 63.7 N

again using the same trig rules

sin(30 deg) = opposite/hypotenuse
= (green O) / 63.7
then (green O) = 63.7 x sin(30 deg) = 63.7 * 0.5 = 31.85 N = friction force






hope this helped

thank you =)