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10 Cards in this Set
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- Back
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Define Momentum |
Momentum is the relationship between mass and velocity.
P = mv |
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Define Impulse |
Impulse is the change in momentum. It can also be defined as a given force over time.
J = Pf - Po = Ft |
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Two cars are driving at each other. Car A weighs 1000 kg and is driving 10 m/s to the right while Car B weighs 2000 kg and driving 2 m/s to the left. After the collision Car B is now moving to the right at 4 m/s. What is Car A's final velocity? |
Po = Pf MaVa + MbVb = MaVa + MbVb (1000*10) + (2000*-2) = (1000*V) + (2000*4) 10,000 - 4,000 = 1,000V + 8,000 6,000 - 8,000 = 1,000V 1,000V = -2,000 V = -2 m/s |
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Two cars collide head on. Car A has a mass of 1000 kg and was traveling 5 m/s to the right. Car B has a mass of 2000 kg and was traveling 2 m/s to the left. If Car A leaves the collision by traveling 3 m/s to the right, what is the speed of Car B after the collision? |
Po = Pf MaVa + MbVb = MaVa + MbVb (1000*5) + (2000*-2) = (1000*3) + (2000V) 5,000 - 4,000 = 3,000 + 2,000V 1,000 - 3,000 = 2,000V 2,000V = -2,000 V = -1 m/s
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Two kids collided and came to rest. If kid A was moving 3 m/s to the right and had a mass of 30kg while kid B was moving 4 m/s to the left and had a mass of 20kg then what has the impulse exerted on kid B by kid A? |
We are talking about Kid B, who has a mass of 20 kg. His Vo = -4m/s and his final velocity is 0 since they are at rest. J = Pf-Po J = MVf - MVo J = (20*0) - (20*-4) J = 80 Ns |
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Two kids collided and came to rest. If kid A was moving 2.67 m/s to the right and had a mass of 30kg while kid B was moving 4 m/s to the left and had a mass of 20kg then what has the impulse exerted on kid A by kid B? |
We are talking about Kid A, who has a mass of 30 kg. His Vo = 2.67 m/s and his final velocity is 0 since they are at rest. J = Pf-Po J = MVf - MVo J = (30*0) - (30*2.67) J = -80 Ns |
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A baseball pitcher throws a fast ball with a 100 Ns Impulse. If he applied the force in 0.15 seconds, what force did he apply? |
J = Ft F = J/t F = 100/0.15 F = 66.67 N |
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If a car has a change of momentum of 240 Ns and it took 2 minutes to change its speed, then what force caused the change? |
J = change in momentum J = Ft but t is in seconds (120 seconds) F = J/t F = 240/120 F = 2N |
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What is the change in momentum of a 950 kg car that travels from 40 m/s to 31 m/s? |
P = MVf - MVo P = (950*31)-(950*40) P = -8550 Ns |
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What is the speed of a 0.050 kg bullet that has a momentum of 1520 Ns? |
P = MV V = P/M V = 1520/0.05 V = 30,400 m/s |
