Physics - Chapter 4

A 10-kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block in meters per second per second is

1

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is

10 times as much

The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is

10N

A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet's acceleration in meters per second per second when taking off?

2

A car traveling at 22 m/s comes to an abrupt halt in 0.1 second when it hits a tree. What is the deceleration in meters per second per second of the car?

220

A ride on a roller-coaster car containing 6 passengers takes 3 minutes. Neglecting friction, a similar ride with 12 passengers aboard would take

3 Minutes

A girl pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon's acceleration in meters per second per second?

3.0

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was

30 m/s

A man weighing 800 N stands at rest on two bathroom scales so that his weight is distributed evenly over both scales. The reading on each scale is

400N

A 10-N falling object encounters 10 N of air resistance. The net force on the object is

0N

An apple weighs 1 N. When held at rest above your head, the net force on the apple is

0N

When a woman stands at rest with both feet on a scale, it reads 500 N. When she gently lifts one foot, the scale reads

500N

A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about

50N

An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is

5N

A rock is thrown vertically into the air. At the top of its path, its acceleration in meters per second per second is

9.8N

A ball is thrown vertically into the air. Because of air resistance, its time coming down compared to its time going up is

More

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same

None of these

The maximum acceleration of a car while towing a second car twice its mass, compared to its acceleration with no car in tow, is

One third

A feather and a coin will have equal accelerations when falling in a vacuum because

the ratio of each object's weight to its mass is the same

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 in meters per second per second is

0

If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is

About 4

The human body can, under certain conditions, withstand an acceleration of 10 g. What net force would produce this acceleration of a 50-kg person?

About 5000N

If the mass of an object does not change, a constant net force on the object produces constant

Acceleration

Which has zero acceleration? An object

All of these

A skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration

Decreases

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

Equal to its weight

The newton is a unit of

Force

A coconut and a feather fall from a tree through the air to the ground below. The amount of air-resistance force is

Greater on the coconut

An object following a straight-line path at constant speed

Has zero acceleration

If a non-rotating object has no acceleration, then we can say for certain that it is

In mechanical equilibrium

If an object's mass is decreasing while a constant force is applied to the object, the acceleration

Increases

A lightweight feather slides off a table and falls through the air until it reaches the floor. During the time of its fall, its acceleration

Is sometimes zero

A kilogram is a measure of an object's

Mass

A light woman and a heavy man jump from an airplane at the same time and open their same-size parachutes at the same time. Which person will get to a state of zero acceleration first?

The light women

A rock weighs 30 N on Earth. A second rock weighs 30 N on the moon. Which of the two rocks has the greater mass?

The one on the moon

The brakes of a speeding truck are slammed on and it skids to a stop. If the truck were heavily loaded so that it had twice the total mass, the skidding distance would be

The same

An object is propelled along a straight-line path by a force. If the net force were doubled, the object's acceleration would be

Twice as much