1 A 0.10-kilogram model rocketís engine is designed to deliver an impulse  of 6.0 newton seconds. If the rocket engine burns for 0.75 second, what average force does it produce?

(1) 4.5 N      (3) 45 N
(2) 8.0 N      (4) 80. N

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Base your answers to questions 12 and 13 on the information and diagram below. The diagram shows a compressed spring between two carts initially at rest on a horizontal frictionless surface. Cart A has a mass of 2 kilograms and cart B has a mass of 1 kilogram. A string holds the carts together.

2 What occurs when the string is cut and the carts move apart?

(1) The magnitude of the acceleration of cart A is one-half the
magnitude of the acceleration of cart B.
(2) The length of time that the force acts on cart A is twice the
length of time the force acts on cart B.
(3) The magnitude of the force exerted on cart A is one-half the
magnitude of the force exerted on cart B.
(4) The magnitude of the impulse applied to cart A is twice the
magnitude of the impulse applied to cart B.

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3 After the string is cut and the two carts move apart, the magnitude of which quantity is the same for both carts?

(1) momentum     (3) inertia
(2) velocity           (4) kinetic energy

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4 An object moving at a constant speed of 25 meters per second possesses 450 joules of kinetic energy. What is the objectís mass?

(1) 0.72 kg    (3) 18 kg
(2) 1.4 kg      (4) 36 kg

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5 The diagram below shows a moving, 5.00-kilogram cart at the foot of a hill 10.0 meters high. For the cart to reach the top of the hill, what is the minimum kinetic energy of the cart in the position shown? [Neglect energy loss due to friction.]

(1) 4.91 J     (3) 250. J
(2) 50.0 J     (4) 491 J

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