In Example 3.4 there are external forces acting on the

Mass is related to an objects ___. (3.1) (a) weight (b) inertia (c) density (d) all of the preceding

What is a possible state of an object in the absence of a net force? (3.2) (a) at rest (b) constant speed (c) zero acceleration (d) all of the preceding

What term refers to the tendency of an object to remain at rest or in uniform, straight-line motion? (3.2) (a) mass (b) force (c) inertia (d) external force

What is necessary for a change in velocity? (3.3) (a) inertia (b) an unbalanced force (c) a zero net force (d) a change in direction

According to Newtons second law of motion, when an object is acted upon by an unbalanced force, what can be said about the acceleration? (3.3) (a) It is inversely proportional to the objects mass. (b) It is zero. (c) It is inversely proportional to the net force. (d) It is independent of mass

A net force ___. (a) can produce motion (b) is a scalar quantity (c) is capable of producing a change in velocity (d) both (a) and (c)

For every action force, there is which of the following? (3.4) (a) a net force (b) a friction force (c) an unbalanced force (d) an equal and opposite force

Which is true of the force pair of Newtons third law? (3.4) (a) The two forces never produce an acceleration. (b) The two forces act on different objects. (c) The two forces always cancel each other. (d) The two forces are in the same direction.

Which is true about the acceleration due to gravity? (3.5) (a) It is a universal constant. (b) It is a fundamental property. (c) It decreases with increasing altitude. (d) It is different for different objects in free fall.

What is true about the constant G? (3.5) (a) It is a very small quantity. (b) It is a force. (c) It is the same as g. (d) It decreases with altitude.

A childs toy floats in a swimming pool. The buoyant force exerted on the toy depends on the volume of ___. (3.6) (a) water in the pool (b) the pool (c) the water displaced (d) the toy under water

If a submerged object displaces an amount of liquid with a weight less than its own, when the object is released, it will ___. (3.6) (a) sink (b) remain submerged in equilibrium (c) float (d) pop up out of the surface

If a submerged object displaces a volume of liquid of greater weight than its own and is then released, what will the object do? (a) sink (b) rise to the surface and float (c) remain at its submerged position

A change in linear momentum requires which of the following? (3.7) (a) a change in velocity (b) an unbalanced force (c) an acceleration (d) all of these

Angular momentum is conserved in the absence of which of the following? (3.7) (a) inertia (b) gravity (c) a net torque (d) linear momentum

Explain the kick of a rifle in terms of Newtons third law. Do the masses of the gun and the bullet make a difference?

Show that the universal gravitational constant G has units of N ? m2/kg2.

Show that the universal gravitational constant G has units of N ? m2/kg2.

Explain why the acceleration due to gravity on the surface of the Moon is one-sixth that of the acceleration due to gravity on the Earths surface.

An astronaut has a mass of 70 kg when measured on the Earth. What is her weight in deep space far from any celestial object? What is her mass there?

Is zero g possible? Explain.

In Chapter 1.6 in the discussion of the hydrometer, it is stated: The higher the bulb floats, the greater the density of the liquid. Why is this? (See Fig. 1.14.)

What is a major consideration in constructing a life jacket that will keep a person afloat?

As learned in Chapter 1.5, 1 L of water has a mass of 1 kg. A thin, closed plastic bag (negligible weight) with 1 L of water in it is lowered into a lake by means of a string and submerged. When fully submerged, how much force would you have to exert on the string to prevent the bag from sinking more?

A large piece of iron with a volume of 0.25 m3 is lowered into a lake by means of a rope until it is just completely submerged. It is found that the support on the rope is less than when the iron is in air. How does the support vary as the iron is lowered more?

Is it easier for a large person to float in a lake than a small person? Explain.

Why must a helium balloon be held with a string?

What are the units of linear momentum?

Explain how the conservation of linear momentum follows directly from Newtons first law of motion.

In Example 3.4 there are external forces acting on the masses. (a) Identify these forces. (b) Why is the linear momentum still conserved?

When a high diver in a swimming event springs from the diving board and tucks in, a rapid spin results. Why?