1) You throw a stone vertically upward, and it feels no air resistance. Once it

Question

1) You throw a stone vertically upward, and it feels no air resistance. Once it is free of your hand but moving upward, the two forces acting on it are the downward pull of gravity and the upward force due to its motion. A) True B) False

2) When a small car is towing a large car by a very light (massless) horizontal rope, the rope exerts equal size forces on both cars. A) True B) False

3) A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s. The vector sum of all the forces acting on this crate must point down the ramp. A) True B) False

4) A 75 pound box rests on a perfectly smooth frictionless horizontal surface. Any horizontal force greater than zero will cause it to start moving. A) True B) False

5) A stone slides down a sloping hillside. The normal force that the surface of the hill exerts on the stone is equal to the stone's weight. A) True B) False

6) An ordinary car would not be able to go around an unbanked curve of a perfectly smooth frictionless road, no matter how the driver turned the wheels. A) True B) False

7) If you swing a ball in a vertical circle using a thin string, at the bottom of the circle the tension in the string must be greater than the ball's weight. A) True B) False

8) A box of mass m is pulled with a constant acceleration a along a horizontal frictionless floor by a wire that makes an angle of 15° above the horizontal. If T is the tension in this wire, then A) T = ma. B) T > ma. C) T < ma.

9) You are standing in a moving bus, facing forward, and you suddenly fall forward as the bus comes to an immediate stop. The force acting on you that causes you to fall forward is A) the force of gravity. B) the normal force due to your contact with the floor of the bus. C) the force due to static friction between you and the floor of the bus. D) the force due to kinetic friction between you and the floor of the bus. E) No forces were acting on you to cause you to fall.

10) Two bodies P and Q on a smooth horizontal surface are connected by a light cord. The mass of P is greater than that of Q. A horizontal force (of magnitude F) is applied to Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be

Explanation / Answer

1) False

Explanation :- you throw a stone vertically upward, and it feels no air resistance. Once it is free of your hand but

moving upward, the two forces acting on it are the downward pull of gravity and the upward force due to its motion.

2) True

3) False

if the speed and direction are constant there is no acceleration thus there is no net force acting on the crate so the

vector sum of all the forces is zero.

4) True

Since the horizontal surface is perfectly smooth, then there is no way for a frictional force to prevent horizontal

motion.The box is at rest, and so the only force acting on it is the weight pulling it down to the table and the normal

force acting against the weight of the box. The box is not falling into the table so the weight (W=mg) equals the

normal force.

5) False

A stone rolls down a sloping hillside.The normal force that the surface of the hill exerts on the stone is equal to the

stone’s weight.

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