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A 10 kg ball flies at 2 m/s towards a 200 kg tiger. If the tiger remains stationary the whole time, what is the velocity of the ball after the tiger bats it towards the direction it came?
0.1
-1 THIS ONE
0
3
A 3 kg osprey dives at 30 m/s and snatches a 0.5 kg fish from the surface of the water. If the fish was approximately stationary, what is the velocity of the osprey as it flies away with its dinner?
25.7 THIS ONE
12.4
44.8
75
To solve these questions, we can use the principle of conservation of momentum. According to this principle, the total momentum before an event is equal to the total momentum after the event, as long as no external forces act on the system.
In the first question, we have a ball flying towards a stationary tiger. Since the tiger remains stationary, its initial velocity is zero. We can calculate the initial momentum of the ball as:
Initial momentum of the ball = mass of the ball × initial velocity of the ball
= 10 kg × 2 m/s
= 20 kg·m/s
Now, when the tiger bats the ball towards the direction it came, the ball experiences a change in direction. However, the magnitude of its velocity remains the same. Therefore, the velocity of the ball after being batted by the tiger is still 2 m/s but in the opposite direction.
Hence, the correct answer is 0.
In the second question, an osprey dives at a certain velocity and snatches a fish from the surface of the water. The initial momentum of the osprey can be calculated as:
Initial momentum of the osprey = mass of the osprey × initial velocity of the osprey
= 3 kg × 30 m/s
= 90 kg·m/s
The fish is approximately stationary, so it has an initial velocity of 0 m/s. After snatching the fish, the osprey carries the fish away. Since the osprey and the fish are now moving together, the final momentum of the combined system remains equal to the initial momentum of the osprey.
Hence, the velocity of the osprey after snatching the fish is:
Velocity of the osprey after snatching the fish = initial momentum of the osprey / mass of the combined system
= 90 kg·m/s / (3 kg + 0.5 kg)
= 90 kg·m/s / 3.5 kg
≈ 25.7 m/s
Thus, the correct answer is 25.7.