PHYS1001 Exam 1: Chapter 4

An apple at rest weighs 1N. The net force on the apple when it is in free fall is..?

1 N

The mass of a per turtle that weighs 10 N is about..?

1 kg

A rock is thrown vertically into the air. At the top of its path, its acceleration is..?

10 m/s2

A 10-N block and a 1-N block lie on a horizontal frictionless table. To impact equal horizontal accelerations, we would have to push the heavier block with..?

10 times as much force

A push on a 1 kg brick accelerates the brick. Neglecting friction, to equally accelerate a 10 kg brick, one would have to push..?

10 times as much force

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

10 times more than the force on the apple

A bag of groceries that has a mass of 10 kilograms weighs about..?

100N

A 1-kg ball is thrown at 10m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about..?

10N

A 1-kg mass at the Earth's surface weighs..?

10N

A 1-kg rock that weighs 10 N is thrown straight upward at 20m/s. Neglecting air resistance, the net force that acts on it when it is half way to the top of its path is..?

10N

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

10N

The mass of a lamb that weighs 110N is about..?

11kg

An object released from rest on another planet requires one second to fall a distance of 6 meters. What is the acceleration due to gravity on this planet..?

12m/s2

A tow truck exerts a force of 3000 N on a car, which then accelerates at 2 m/s2. What is the mass of the car..?

1500 kg

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

1m/s2

A car has a mass of 1000 kg and accelerates at 2 m/s2. What net force is exerted on the car...?

2000N

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

220 m/s2

What horizontally-applied force will accelerate a 400-kg crate at 1 m/s2 across a factory floor against a friction force half its weight..?

2400N

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..?

2m/s2

Nellie 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..?

3.0 m/s2

A 300-kg bear grasping a vertical three slides down at constant velocity. The friction force between the tree and the bear is..?

3000N

A 500-N parachutist opens his chute and experiences an air resistance force of 800N. The net force on the parachutist is then..?

300N upward

A 1000-kg automobile enters a freeway on-ramp at 20m/s and accelerates uniformly up to 40m/s in a time of 10 seconds. How far does the automobile travel during that time..?

300m

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

30m/s

An astronaut on another planet drops a 1-kg rock from rest. The astronaut notices that the rock falls 2 meters straight down in one second. On this planet, how much does the rock weigh..?

4N

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

4s

Scotty Skydiver of mass 100 kg experiences air resistance of 500 N, and an acceleration of about..?

0.5g

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

0N

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

0N

A sack of potatoes weighing 200N falls from an airplane. As the velocity of fall increases, air resistance also increases. When air resistance equals 200N, the sac's acceleration becomes..?

0m/s2

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

5000N

Phil stands at rest with both feet on a scale that reads 500N. When he gently lifts one foot, the scale reads..?

500N

Suzie Skydiver, who weighs 500N, reaches terminal velocity of 90km/h. The air resistance on Suzie is then..?

500N

A 10-kilogram block with an initial velocity of 10m/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

A mobile phone is pulled northward by a force of 10 N and at the same time pulled southward by another force of 15 N. The resultant force on the phone is..?

5N

An astronaut on another planet drops a 1-kg rock from rest and finds that it falls a vertical distance of 2.5 meters in one second. On this planet, the rock has a weight of..?

5N

A 10-N falling object encounters 4N of air resistance. The net force on the object is..?

6N

A block is dragged without acceleration in a straight-line path across a level surface by a force of 6 N. What is the force of friction between the block and the surface..?

6N

In which case would you have the largest mass of gold? If your chunk of gold weighed 1 N on the..?

Moon

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

More

An object's weight is properly expressed in units of..?

Newtons

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

None of the above -mass -volume -weight

A car by itself is capable of a certain maximum acceleration. When it tows a car of the same mass, its maximum acceleration is..?

One half

A car by itself is capable of a certain maximum acceleration. When it tows a twice-as-massive car, its maximum acceleration is..?

One third

If you double the net force on an object, you'll double its..?

Speed

Two factors that greatly affect air resistance on falling objects are frontal area and..?

Speed

Your weight as measured on your bathroom scale is..?

The force due to gravity on you

When the bottom string is pulled slowly in the heavy-ball-and-strings demonstration (Figure 4.8 in your book), tension..?

in the top string is due to your pull plus the weight of the ball

Whenever the net force on an object is zero, its acceleration..?

is Zero

A skydiver steps from a helicopter and falls for a few seconds until terminal velocity is reached. Thereafter, until he opens his parachute, his acceleration..?

is zero

A single brick falls with acceleration g. The reason a double brick falls with the same acceleration is..?

its ratio of force to mass is the same

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

mg

When you stand at rest with your left foot on one bathroom scale an your right foot on a similar scale, each of the scales will..?

show readings that when added equal your weight

Strange as it may seem, it is just as difficult to accelerate a car on a level surface on the Moon as it is here on Earth because..?

the mass of the car is independent of gravity

A boulder following a straight-line path at constant velocity has..?

zero acceleration

A kilogram is a measure of an object's..?

Mass

Neglecting friction, a small and a large block of ice begin sliding down an incline together. The larger block reaches the bottom..?

at the same time as the small block

A ball is thrown vertically in the air. Because of air resistance, its peed when it returns to its starting level compared with its initial speed is..?

Less

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity, the object..?

Accelerates in the direction of the applied force

A constant net force on a rail-road car produces constant..?

Acceleration

If an apple experiences a constant net force, it will have a constant..?

Acceleration

Which has zero acceleration? An object..?

All of the above -at rest -moving at constant velocity - in mechanical equilibrium

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has twice as much..?

All of the above -inertia -mass -volume

Recall Galileo's Leaning Tower experiment. With negligible air resistance, a heavy and a light object fall..?

All of the above -with equal accelerations -with the same increases in speed -to the ground in equal times

Which has the greater mass..?

An automobile battery

At equilibrium on a bathroom weighting scale, the downward pull of gravity on you is balanced by..?

An upward support force

A heavy ball hangs by a string, with a second string attached to its bottom. A quick pull on the bottom string breaks the..?

Bottom string

A ball thrown straight upward takes 10 seconds to go up-and-down round trip. Because of air resistance, the time taken for the ball just to go up is..?

Less than 5s

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it..?

Continues at the speed it had when it encountered the second force

Suzie Skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration..?

Decreases

If less horizontal force is applied to a sliding object than is needed to maintain a constant velocity, the object..?

Eventually slides to a stop

The newton is a unit of..?

Force

A large and a small person wish to parachute at equal terminal velocities. The larger person will have to..?

Get a larger parachute

A coconut and a bird's feather fall from a tree through the air to the ground below. The force of air resistance is..?

Greater on the coconut

If the mass of a cart is quickly loaded to have twice the mass while a propelling force remains constant, the cart's acceleration..?

Halves

A skydiver's terminal velocity will be greatest if she falls..?

Head first

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...?

Heavier object

A heavy rock and a light rock of the same size are falling through the air from a tall building. The one the encounters the greatest air resistance is the..?

Heavy rock

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

In mechanical equailibrium

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

Increases

An object with twice as much mass as another object has twice as much..?

Inertia

A heavy block at rest is suspended by vertical rope. When the block accelerates upward by the rope, the rope tension..?

Is greater than its weight

If the net force on a cart is tripled, the cart's acceleration..?

Is three times as much

Two tennis balls fall through the air from a tall building. One of them is filled with lead pellets. The ball to reach the ground first is the..?

Lead-filled ball

A ball is thrown upwards and caught when it returns. Compared with its initial speed and in the presence of air resistance, the speed with which it is caught is always..?

Less

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 the ground first..?

The heavy man

A light women 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 woman

When a constant and sustained upward force acts on a rocket, its acceleration increases mainly because..?

The mass of the rocket decreases as fuel is burned

A rock weighs 30 N on Earth and another rock weighs 30 N on the Moon. Which rock has the greater mass..?

The one on the Moon

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

The ratio of both the feather's and coin's weight to mass is the same

A bowling ball and a baseball accelerate equally when falling in a vacuum because..?

The ratio of their weights to mass is the same

A net force 1 N accelerates 1-kg box at the rate of 1m/s2. The acceleration of a 2-kg box by a net force of 2N is..?

The same

Compared to the mass of an apple on Earth, the mass of the apple on the Moon is..?

The same

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

A heavy ball hangs by a string, with a second string attached to its bottom. A slow pull on the bottom string breaks the..?

Top string

The force required to maintain a constant velocity for an astronaut in free space is equal to..?

Zero

When a falling object has reached its terminal velocity, its acceleration is..?

Zero

You drive your car at a constant 60 km/h along the highway. You apply the brakes until the car slows to 40 km/h. If at that moment you suddenly release the brakes, the car tends to..?

continue moving at 40km/h