physics Chapter 2&3

A 15-N force and a 45-N force act on an object in opposite directions. What is the net force on the object? a. 15N b. 30N c. 45N d. 60N

a. 15N

What is the minimum resultant possible when adding 5-N force to an 8-N force? a. 5 N b. 3 N c. 8 N d. 13 N e. 40 N

a. 5 N

After a cannonball is fired into frictionless space, the amount of force needed to keep it going equals a. zero, since no force is necessary to keep it moving b. twice the force with which it was fired c. one half the force with which it was fired d. the same amount of force with which it was fired e. one quarter the force with which it was fired

a. zero, since no force is necessary to keep it moving

The mass of a lamb that weighs 110 N is about a. 1 kg b. 11 kg c. 110 kg d. 1100 kg

b. 11 kg

A girl whose weight is 500 N hangs from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand? a. 0 N b. 250 N c. 500 N d. 750 N e. 1000 N

b. 250 N

You and a friend are jumping on a trampoline. Why does Earth, which is rapidly orbiting around the sun, not move under you feet when you jump? a. There are different rules in space and on the surface of the earth b. Newton's first law holds that your body moves along with Earth because it is not compelled to change its motion by an unbalance force c. Newton's second law holds that the acceleration produced by the force of gravity is offset by the force of friction on your feet d. Newton's third law holds that there is an equal and opposite force exerted by the trampoline on your feet, which allows you to move with Earth through space

b. Newton's first law holds that your body moves along with Earth because it is not compelled to change its motion by an unbalance force

You are helping your aunt move a piano on wheels from one room to another. When you push the piano horizontally, it moves at constant speed. What can you say about the piano? a. it's in static equilibrium b. it's in dynamic equilibrium c. it's in equilibrium because it doesn't experience net force opposite to the friction force

b. it's in dynamic equilibrium

A scalar quantity has a. only direction b. only magnitude c. both d. neither

b. only magnitude

Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane? a. the ball would not roll up the other plane at all b. to nearly its original height c. to about one quarter its original height d. to nearly twice its original height e. to nearly half its original height

b. to nearly its original height

A bag of sports equipment has a mass of 10.0 kilograms and a weight of a. 0.98 N b. 9.8 N c. 98 N d. 980 N

c. 98 N

What is needed to describe a vector quantity? a. only magnitude b. only direction c. both magnitude and direction d. neither magnitude nor direction

c. both magnitude and direction

An object following a straight-line path at constant speed a. has no force acting on it b. has a net force acting on it in the direction of motion c. has zero acceleration d. must be moving in a vacuum

c. has zero acceleration

If the force of gravity suddenly stopped acting on the planets, the would a. spiral slowly towards the sun b. continue to orbit the sun c. move in straight lines tangent to their orbits d. spiral slowly away from the sun e. fly straight away from the sun

c. move in straight lines tangent to their orbits

What is the maximum resultant possible when adding 2-N force to an 8-N force? a. 2N b. 6N c. 8N d. 10N e. 16N

d. 10N

How much does a 3.0-kg bag of bolts weigh? a. 7.2 N b. 14.4 N c. 22.8 N d. 29.4 N e. 58.8 N

d. 29.4 N

A 5-N force and a 30-N force act in the same direction on an object. What is the net force on the object? a. 5N b. 25N c. 30N d. 35N

d. 35N

The astronomer Copernicus publicly stated in the 1500s that Earth a. does not move d. revolves around the sun c. is slowing down d. moves in a straight line e. is the center of the solar system

d. revolves around the sun

The weight of a person can be represented by a vector that acts a. in a direction that depends on where the person is standing b. perpendicular to the ground underneath the person c. parallel to the ground d. straight down, even if the person is standing on a hill

d. straight down, even if the person is standing on a hill

A barrage is being pulled along a canal by two ropes that make equal angled with the direction in which the barge points. Assuming the two pulls on the barge are equal, in what direction does the barge move? a. It oscillates back and forth between the two banks b. it moves straight ahead c. it moves in the direction of the resultant force on it d. both a & b e. both b & c

e. both b & c