Because of your interest in the environment and your physics experience, you are
ID: 1787590 • Letter: B
Question
Because of your interest in the environment and your physics experience, you are assisting the Campus Museum of Natural History in the production of an animated film about hawks. In the script, a m1=1.5 kg hawk hovers motionless with respect to the ground when it sees a goose flying below it. The hawk dives straight down, striking the goose at a speed of v1=60 km/hr and digging its claws into the goose's body. The m2=2.5 kg goose was flying north horizontally at v2=30 km/hr just before it was struck by the hawk and killed. The animators want to know the velocity of the birds just after the strike.
Explanation / Answer
The velocity of the hwak is 60 km/hr=60×5/18=50/3m/s
The mass of hwak is 1.5 kg
The momentum of hawk before striking the goose is m×v=1.5×50/3=25kgm/s
The mass of goose is 2.5kg
The velocity of goose is 30km/hr=25/3m/s
The momentum of goose at the instant of collision is m×v=2.5×25/3=62.5/3=20.833kgm/s
Since no external force is acting the momentum of the system before collision is equal to momentum of the system after collision
After collision the mass of the system is 4kg
Let the combined velocity be V
Then the momentum is 4×V
25+62.5/3=4×V
137.5/3=4×V
137.5/12=V
The resultant velocity is making an angle ¢
Tan¢=30/60=1/2=0.5
¢=26.5650 with the vertical
V=11.45833m/s