Chapter 3+4

If a car increases its velocity from zero to 60 m/s in 10 seconds, its acceleration is A) 3 m/s2. B) 6 m/s2. C) 60 m/s2. D) 600 m/s2.

B) 6 m/s2.(Acceleration)

An airplane that flies at 100 km/h in a 100-km/h crosswind has a ground speed of A) 0 km/h. B) 100 km/h. C) 141 km/h. D) 200 km/h.

C) 141 km/h.(Velocity Vectors)

If a stone falls to the bottom of a mineshaft in 6 seconds, then the depth of the shaft is about A) 60 m. B) 120 m. C) 180 m, D) more than 200 m.

C) 180 m.(Free Fall)

The two measurements necessary for calculating average speed are A) acceleration and time. B) velocity and time . C) distance and time. D) distance and acceleration. E) velocity and distance.

C) distance and time.(Speed and Velocity)

The distance a freely falling bowling ball falls each second A) is about 5 m. B) is about 10 m. C) increases. D) none of these.

C) increases.(Free Fall)

When you walk at an average speed of 4 m/s, in 5 s you'll cover a distance of A) 2 m. B) 10 m. C) 15 m. D) 20 m.

D) 20 m.(Speed and Velocity)

A car has a mass of 1000 kg and accelerates at 2 m/s2. What net force is exerted on the car? A ) 500 N B) 1000 N C) 1500 N D) 2000 N E) none of these.

D) 2000 N.(Newton's Second Law of Motion)

A 500-N parachutist opens his chute and experiences an air resistance force of 800 N. The net force on the parachutist is then A) 300 N downward. B) 500 N downward. C) 800 N downward. D) 300 N upward. E) 500 N upward.

D) 300 N upward(When Acceleration is Less than g-Nonfree Fall)

A car's speed 3 seconds after accelerating from rest at 2 m/s2 is A) 2 m/s. B) 3 m/s. C) 4 m/s. D) 6 m/s.

D) 6 m/s.(Acceleration)

An apple weighs 1 N. When the apple is held at rest above your head, the net force on the apple is A) 0 N. B) 0.1 N. C) 1 N. D) 9.8 N. E) none of these.

A) 0 N.(Newton's Second Law of Motion)

A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the opposite direction has a speed of A) 0 m/s. B) 3 m/s. C) 4 m/s. D) 6 m/s.

A) 0 m/s. 3 (Motion is Relative)

An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration is A) 0 m/s2. B) 5 m/s2. C) 8 m/s2. D) 24 m/s2.

A) 0 m/s2.(Acceleration)

A sack of potatoes weighing 200 N falls from an airplane. As the velocity of fall increases, air resistance also increases. When air resistance equals 200 N, the sack's acceleration becomes A) 0 m/s2. B) 5 m/s2. C) 10 m/s2. D) infinite. E) none of these.

A) 0 m/s2.(When Acceleration is Less than g-Nonfree Fall)

The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about A) 1 s. B) 2 s. C) 10 s. D) not enough information

A) 1 s.(Free Fall)

A pot that falls from a ledge and hits the ground 45 m below hits the ground at A) 30 m/s. B) 60 m/s. C) 120 m/s. D) more than 120 m/s:

A) 30 m/s.(Free Fall)

Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the opposite direction. Jake's speed relative to the ground is A) 6 m/s. B) 10 m/s. C) 14 m/s. D) none of these

A) 6 m/s.(Speed and Velocity)

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity, the object A) accelerates in the direction of the applied force. B) accelerates opposite the direction of the applied force. C) experiences greater friction. D) none of these.

A) accelerates in the direction of the applied force.(Newton's Second Law of Motion)

The newton is a unit of A) force. B) mass. C) density. D) inertia.

A) force(Mass and Weight)

A skydiver's terminal velocity will be greatest if she falls A) head first. B) lying flat on her back. C) lying flat on her stomach. D) with her parachute open.

A) head first(When Acceleration is Less than g-Nonfree Fall)

An object with twice as much mass as another object has twice as much A) inertia. B) speed. C) acceleration due to gravity. D) all of these

A) inertia.(Mass and Weight)

The accelerations possible for a ball on an inclined plane A) range from zero to g. B) range from g to infinity. C) have no limit.

A) range from zero to g.(Acceleration)

When a falling object has reached its terminal velocity, its acceleration is A) zero. B) g. C) constant.

A) zero.(When Acceleration is Less than g-Nonfree Fall)

If you double the net force on an object, you'll double its A) acceleration. B) speed. C) velocity. D) all these.

B(Force Causes Acceleration)

A cart changes its speed from 90 m/s to 100 m/s in 10 seconds. During this interval its acceleration is A) zero. B) 1 m/s2. C) 10 m/s2. D) none of these.

B) 1 m/s2.(Acceleration)

If you throw a ball straight downward (in the absence of air resistance), after leaving your hand its acceleration is A) less than 10 m/s2. B) 10 m/s2. C) greater than 10 m/s2.

B) 10 m/s2.(Free Fall)

A rock is thrown vertically into the air. At the top of its path, its acceleration is A) zero. B) 10 m/s2. C) between 0 and 10 m/s2. D) greater than 10 m/s2.

B) 10 m/s2.(Newton's Second Law of Motion)

A ball is projected 125 meters straight upward and then falls the same distance back to its starting point. Neglecting air resistance, its total time in the air is about A) 5 s. B) 10 s. C) 15 s. D) more than 20 s.

B) 10 s.(Free Fall)

A push on a 1-kg brick accelerates it. Neglecting friction, equally accelerating a 10-kg brick requires A) just as much force. B) 10 times as much force. C) 100 times as much force. D) one-tenth the amount of force. E) none of these.

B) 10 times as much force.(Newton's Second Law of Motion)

The time it takes a car to attain a speed of 30 m/s when accelerating from rest at 2 m/s2 is A) 2 s. B) 15 s. C) 30 s. D) 60 s. E) none of these.

B) 15 s.(Acceleration)

The total time it takes a projectile fired straight up at 10 m/s to reach the top of its path and return to its starting point is about A) 1 s. B) 2 s. C) 10 s. D) 20 s.

B) 2 s. 3(Free Fall)

The average speed of a horse that gallops 10 kilometers in 30 minutes is A) 15 km/h. B) 20 km/h. C) 30 km/h. D) 40 km/h. B) 20 km/h.(Speed and Velocity)

B) 20 km/h.(Speed and Velocity)

If a freely falling object were equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s2, then its speed reading would increase each second by A) 10 m/s. B) 20 m/s. C) 30 m/s. D) 40 m/s . E) depends on its initial speed.

B) 20 m/s.(Free Fall)

An 80-km/h airplane flying against a 10-km/h head wind has a groundspeed of A) 10 km/h. B) 70 km/h. C) 80 km/h. D) 90 km/h.

B) 70 km/h.(Velocity Vectors)

A constant net force on a rail-road car produces constant A) velocity. B) acceleration. C) both of these. D) neither of these.

B) acceleration.(Newton's Second Law of Motion)

A heavy ball hangs by a string, with a second string attached to its bottom. A quick pull on the bottom string breaks the A) top string. B) bottom string. C) top or bottom string equally.

B) bottom string.(Mass and Weight)

If an object moves with constant acceleration, its velocity must A) be constant also. B) change by the same amount each second. C) change by varying amounts depending on its speed. D) always decrease.

B) change by the same amount each second.(Acceleration)

Two objects of the same size, but unequal weights are dropped from a tall tower. Taking air resistance into consideration, the object to hit the ground first will be the A) lighter object. B) heavier object. C) Both hit at the same time. D) not enough information.

B) heavier object.(When Acceleration is Less than g-Nonfree Fall)

If an object's mass is decreasing while a constant force is applied to the object, the acceleration A) decreases. B) increases. C) res.(Newton's Second Law of Motion)emains the same.

B) increases.(Newton's Second Law of Motion)

The speedometer of an automobile reads A) average speed. B) instantaneous speed. C) accelerated speed.

B) instantaneous speed.(Speed and Velocity)

Whenever the net force on an object is zero, its accelerationA) may be less than zero.B) is zero.C) may be more than zero.

B) is zero.(Force Causes Acceleration)

A kilogram is a measure of an object's A) force. B) mass. C) both of these. D) neither of these.

B) mass.(Mass and Weight)

A rock is thrown vertically into the air. At the top of its path the net force on it is A) less than mg. B) mg. C) more than mg.

B) mg. (Newton's Second Law of Motion)

If an apple experiences a constant net force, it will have a constant A) velocity. B) speed. C) acceleration. D) position. E) more than one of these.

B) speed

Your weight as measured on your bathroom scale is A) equal to your mass. B) the force due to gravity on you. C) a property of mechanical equilibrium. D) all of these.

B) the force due to gravity on you.(Mass and Weight)

When a constant and sustained upward force acts on a rocket, its acceleration increases mainly because A) gravity becomes weaker with increased distance. B) the mass of the rocket decreases as fuel is burned. C) No way, for acceleration would be constant.

B) the mass of the rocket decreases as fuel is burned. (Newton's Second Law of Motion)

A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass? A) the one on Earth, B) the one on the Moon C) They have the same mass. D) not enough information.

B) the one on the Moon(Mass and Weight)

A rock dropped from a 5-m height accelerates at 10 m/s2 and strikes the ground 1 s later. If the rock is dropped from a height of 2.5 m, its acceleration of fall is A) half. B) the same. C) twice. D) four times as much.

B) the same.(Acceleration)

A boulder following a straight-line path at constant velocity has A) a net force acting upon it in the direction of motion. B) zero acceleration. C) no forces acting on it. D) none of these.

B) zero acceleration.(Newton's Second Law of Motion) Motion)

An apple at rest weighs 1 N. The net force on the apple when it is in free fall is A) 0 N. B) 0.1 N. C) 1 N. D) 9.8 N. E) none of these.

C) 1 N.(Newton's Second Law of Motion)

A 1-kg mass at the Earth's surface weighs A) 1 N. B) 5 N. C) 10 N. D) 12 N. E) none of these.

C) 10 N(Mass and Weight)

The force of friction on a sliding object is 10 N. The applied force needed to maintain a constant velocity is A) more than 10 N. B) less than 10 N. C) 10 N.

C) 10 N.(Friction)

When a ball thrown straight upwards reaches the very top of its path, its acceleration is A) zero. B) 5 m/s2. C) 10 m/s2. D) none of these

C) 10 m/s2(Free Fall)

One-half second after starting from rest, a freely falling object will have a speed of about A) 2 m/s . B) 5 m/s. C) 10 m/s. D) 20 m/s. E) none of these

C) 10 m/s2.(Free Fall)

A bag of groceries that has a mass of 10 kilograms weighs about A) 1 N. B) 10 N. C) 100 N. D) 1000 N. E) greater than 1000 N.

C) 100 N.

An 80-km/h airplane caught in a 60-km/h crosswind has a resultant speed of A) 60 km/h. B) 80 km/h. C) 100 km/h. D) 141 km/h.

C) 100 km/h.(Velocity Vectors)

Jogging Jake runs at 4 m/s along a train flatcar that moves at 10 m/s in the same direction. Jake's speed relative to the ground is A) 6 m/s. B) 10 m/s. C) 14 m/s. D) none of these.

C) 14 m/s.(Motion is Relative)

A ball starting from rest at the top of an inclined plane gains a speed of 2 m/s for each second it rolls. What is its acceleration down the incline? A) 0.5 m/s2 B) 1 m/s2 C) 2 m/s2 D) 4 m/s2

C) 2 m/s2(Acceleration)

A 1000-kg automobile enters a freeway on-ramp at 20 m/s and accelerates uniformly up to 40 m/s in a time of 10 seconds. How far does the automobile travel during that time? A) 100 m B) 200 m C) 300 m D) 400 m E) none of these.

C) 300 m.(Newton's Second Law of Motion)

If a rocket initially at rest accelerates at a rate of 50 m/s2 for one minute, its speed will be A) 50 m/s. B) 500 m/s. C) 3000 m/s. D) 3600 m/s.

C) 3000 m/s.(Acceleration)

Ten seconds after starting from rest, a car is moving at 40 m/s. What is the car's acceleration? A) 0.25 m/s2 B) 2.8 m/s2 C) 4.0 m/s2 D) 10 m/s2 E) 40 m/s2.

C) 4.0 m/s2(Acceleration)

A humming bird flying at 4 km/h that gets caught in a 3-km/h crosswind has a resultant speed of about A) 3 km/h. B) 4 km/h. C) 5 km/h. D) more than 5 km/h.

C) 5 km/h.(Velocity Vectors)

The human body can withstand an acceleration of 10 g under certain conditions. What net force would produce this acceleration for a 50-kg person? A) 500 N B) 2500 N C) 5000 N D) 25,000 N E) none of these.

C) 5000 N.(Newton's Second Law of Motion)

A 10-N falling object encounters 4 N of air resistance. The net force on the object is A) 0 N. B) 4 N. C) 6 N. D) 10 N. E) none of these.

C) 6 N.(Friction)

A freely-falling watermelon falls with constant A) velocity. B) speed. C) acceleration. D) distances each successive second.

C) acceleration.(Free Fall)

Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom A) before the small block. B) after the small block. C) at the same time as the small block.

C) at the same time as the small block.(Newton's Second Law of motion)

heavy block at rest is suspended by a vertical rope. When the block accelerates upward by the rope, the rope tension A) is less than its weight. B) equals its weight. C) is greater than its weight.

C) is greater than its weight.(Newton's Second Law of Motion)

Phil Physiker standing at the edge of a cliff throws one ball straight up and another ball straight down, both with the same speed. Neglecting air resistance, which ball hits the ground below with the greater speed? A) the one threw upward B) the one threw downward C) neither, both hit with the same speed.

C) neither, both hit with the same speed(Free Fall)

An object's weight is properly expressed in units of A) meters. B) kilograms. C) newtons. D) cubic centimeters.

C) newtons.(Mass and Weight)

Two factors that greatly affect air resistance on falling objects are frontal area and A) mass. B) weight. C) speed.

C) speed (When Acceleration is Less than g-Nonfree Fall)

A bullet is dropped into a river from a very high bridge at the same time as another bullet is fired straight downward from a rifle. Neglecting air resistance, the acceleration just before striking the water is A) greater for the dropped bullet. B) greater for the fired bullet. C) the same for each bullet. D) none of these.

C) the same for each bullet.(Free Fall)

A force of 1 N accelerates 1-kg box at the rate of 1 m/s2. The acceleration of a 2-kg box by a net force of 2 N is A) half as much. B) twice as much. C) the same. D ) none of these.

C) the same(Newton's Second Law of Motion)

A mosquito flying at 3 m/s that encounters a breeze blowing at 3 m/s in the same direction has a speed of A) 0 m/s. B) 3 m/s. C) 4 m/s. D) 6 m/s.

D) 6 m/s.(Motion is Relative)

At one instant an object in free fall is moving downward at 50 m/s. One second later its speed is A) 25 m/s. B) 50 m/s . C) 55 m/s. D) 60 m/s. E) 100 m/s.

D) 60 m/s.(Free Fall)

An 80-km/h airplane flying in the same direction as a 10 km/h tail wind has a groundspeed of A) 10 km/h. B) 70 km/h. C) 80 km/h. D) 90 km/h.

D) 90 km/h.(Velocity Vectors)

Which has zero acceleration? An object A) at rest. B) moving at constant velocity. C) in mechanical equilibrium. D) all of these. E) none of these.

D) all of these.(Newton's Second Law of Motion)

A vehicle undergoes acceleration when it A) gains speed. B) loses speed. C) changes its direction. D) all of these.

D) all of these.(Speed and Velocity)

If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration A) quadruples. B) doubles. C) stays the same. D) halves. E) none of these,

D) halves.(Newton's Second Law of Motion)

Twelve seconds after starting from rest, a freely-falling cantelope has a speed of A) 10 m/s . B) 50 m/s. C) 100 m/s. D) more than 100 m/s.

D) more than 100 m/s.(Free Fall)

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same A) mass. B) volume. C) weight. D) all of these. E) none of these.

E) none of these.(Mass and Weight)