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1 answer:
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The final velocity of the skater is 2.34 m/s forward
Explanation:
We can solve this problem by using the law of conservation of momentum. In fact, the total momentum of the system before and after the ball is thrown must be conserved, in absence of external forces.
Before the ball is thrown, the total momentum is:
where
M = 61 kg is the mass of the skater
m = 4.0 kg is the mass of the ball
u = 2.5 m/s (forward) is the combined velocity of the skater and the ball
After, the ball is thrown at twice the velocity, so the final total momentum is
where
V is the final velocity of the skater
v = 2(2.5) = 5.0 is the final velocity of the ball
Since the total momentum must be conserved, we can write
So, the skater is moving at 2.34 m/s (forward) after the shot.
Learn more about momentum:
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Answer:
The height reached is 20m, The time taken to reach 20m is 2 seconds
Explanation:
Observing the equations of motion we can see that the following equation will be most helpful for this question.
We are given initial velocity, u
We know that the stone will stop at its maximum height, so final velocity, v
Acceleration, a
And we are looking for the displacement (height reached), s
Substitute the values we are given into the equation
Rearrange for s
s = -20 (The negative is just showing direction, it can be ignored for now)
The height reached is 20m
Use a different equation to find the time taken
Substitute in the values we have
Rearrange for t
t = 2s
The time taken to reach 20m is 2 seconds