Physics 1070 Midterm

What is the cost of operating a 3.00-W electric lamp for 2 years if the cost of electricity is $0.0800 per KW.h?

$ 4.2048

What is the acceleration of a car that maintains a constant velocity of 55 mi/hr for 10.0 seconds?

0

The amount of net force required to keep a 5-kg object moving rightward with a constant velocity of 2 m/s is ______________.

0 N

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stop watch measures the ball's trajectory time from table to the floor to be 0.30 s. How far away from the table does the ball land? (g = 9.8 m/s^2) and air resistance is negligible)

0.072 m

Suppose two children push horizontally, but in exactly opposite directions, on a third child in a wagon. The first child exerts a force of 75.0 N, the second a force of 90.0 N, friction is 12.0 N, and the mass of the third child plus wagon is 23.0 kg. What would be the acceleration ?

0.13m/s^2 in the direction of 2nd child push

A 0.5-kg ball moving at 5 m/s strikes a wall and rebounds in the opposite direction with a speed of 2 m/s. If the impulse occurs for a time duration of 0.01 s, then the average force (magnitude only) acting upon the ball is ______________ Newtons.

0.14 or 150 or 350 or 500

Blood is pumped from the heart at a rate of 5.0 L/min into the aorta (of radius 1.0 cm). Determine the speed of blood through the aorta.

0.27 m/s

A ball is rolled horizontally off a table with an initial speed of 0.24 m/s. A stopwatch measures the ball's trajectory time from table to the floor to be 0.30 s. What is the height of the table? (g = 9.8 m/s^2) and air resistance is negligible

0.44 m

A 10-Newton object moves to the left at 1 m/s. Its kinetic energy is approximately ______________ Joules.

0.5

If an object has a mass of 4 grams and a volume of 8 cubic centimeters, what would be its density?

0.5 g/cm^3

A 100-g toy car is propelled by a compressed spring that starts it moving. The car follows the curved track . Show that the final speed of the toy car is___ m/s, if its initial speed is 2.00 m/s and it coasts up the frictionless slope, gaining 0.180 m in altitude.

0.687m/s

A ball is thrown 5m straight up .It takes 0.2 s to return back to the start position. What is the ball displacement after that time ?

0m

A certain man has a mass of 80 kg and a density of 955 kg/m^3 (excluding the air in his lungs). Find the buoyant force air exerts on him. ( air density 129 kg/m^3)

1.02 N or 10.2 kN or 10.2 N or 102 N

How much work is done by the boy pulling his sister 30.0 m in a wagon with angle 48 degrees to the horizontal using force 60.0 N? Assume no friction acts on the wagon.

1.2 kJ

An object is launched at a velocity of 20 m/s in a direction making an angle of 25° upward with the horizontal. What is the total flight time (between launch and touching the ground) of the object?

1.72 s

A 50-kg platform diver hits the water below with a kinetic energy of 5000 Joules. The height (relative to the water) from which the diver dove was approximately ______________ meters.

10

If you push on a wall with a force of -10 Newtons, the force acting on you is

10 Newtons

Some species of whales can dive to the depth of 1 kilometer. What is the total pressure they experience at this depth? (Density = 1020 kg/ m^3 and 100 000 N/m^2= 1 ATM.

100 ATM

An airplane moves at 141 km/h toward the northeast (45 degrees). What is its component velocity in the northward direction?

100 km/h

One kiloPascal is equal to:

1000 Newton of force per square meter

The distance-time graph represents the position of an object moving in a straight line. What is the speed of the object during the time interval t = 2.0 seconds to t = 4.0 seconds?

10m/s

A cube-shaped block of pinewood has a surface area of 9 m² and a density of 0.5 g /cm^3. Its mass equals

13500 kg

What force must be exerted on the master cylinder of a hydraulic lift to support the weight of a 2000-kg car (a large car) resting on the slave cylinder? The master cylinder has a 2.00-cm diameter and the slave has a 24.0-cm diameter.

136 N

An airplane that flies at 100 km/h in a 100 km/h hurricane crosswind has a speed (relative to the ground) of?

141 km/h

If a 10 kilogram object accelerates suddenly at 15 m/s2, how much force was applied to the object?

150 N

How much force is needed to accelerate a 90 kg skier 2 m/s^2

180 N

Mercury (density = 13.6 g/cm^3 ) commonly supplied in flasks containing 34.5 kg . What is the volume in liters (L) of mercury?

2.54 L

A person is pulling west with 35 N of force against a person pulling east with 15 N of force. What is the net force?

20 N west

The average speed of an object which moves 10 kilometers (km) in 30 minutes is ______________.

20 km/hr

Which one of the following quantities is NOT a vector?

20 m/s

A fireman, stays away from a burning building, directs a stream of water from a fire hose at an angle of 30.0° above the horizontal. If the initial speed of the stream is 40.0 m/s, what is maximum height of the water

20.4 m

A student adds two vectors with magnitudes of 200 and 40. Which one of the following is the closest possible choice for the magnitude of the resultant?

200

A ball is kicked with an initial velocity of 16 m/s in the horizontal direction and 12 m/s in the vertical direction. At what speed does the ball hit the ground?

20m/s

Verify the ranges for the projectiles motion for an initial velocity of 50 m/s at the given initial angles= 45 degree. ( g = 9.8 m/s^2

250m

A 4 000 g object has a momentum of 12 kg•m/s. The object's speed is ______________ m/s.

3

If it takes one minute for an airplane to reach speed 100 m/s from start to take -off . How long is the take- off path ( airplane displacement in that time) .

3 km

On takeoff, a rocket accelerates from rest at a rate of 50.0 m/s^2 for exactly 1 minute. The rocket's speed after this minute of steady acceleration will be ______________ m/s.

3.00 x 10^3

How many Joules of energy are in one kilowatt-hour?

3.6 MJ

Which two angles will produce the same range? (in degrees)

30 and 60

A baseball pitcher delivers a fast ball. During the throw, the speed of the ball increases from 0 to 30.0 m/s over a time of 0.100 seconds. The average acceleration of the baseball is ______________ m/s^2

300.

When a teacher stands at the front of the class, the force of gravity pulls her toward the ground. The ground pushes back with an equal and opposite force. This is an example of which of Newton's Laws of Motion?

3rd

Which angle produces the greatest range?

45 degrees

An arrow is drawn back so that 50 Joules of potential energy is stored in the stretched bow and string. When released, the arrow will have a kinetic energy of ______________ Joules.

50

Using 1kJ of work, a small object is lifted from the ground floor to the third floor of a tall building in 20.0 seconds. What power was required in this task?

50 W

A platform diver weighs 500 N. She steps off a diving board that is elevated to a height of 10 meters above the water. The diver will possess ______________ Joules of kinetic energy when she hits the water.

5000

A bullet in a gun is accelerated from the firing chamber to the end of the barrel at an average rate of 6.20×10^5 m/s^2 for 8.10×10^−4 s. What is its muzzle velocity (that is, its final velocity)?

502 m/s

A powerful motorcycle can accelerate from rest to 26.8 m/s (100 km/h) in only 3.90 s. How far does it travel in that time?

52.3 m

Two people are pulling a refrigerator into a garage. One person is pulling south with 30 N of force, while the other person is pulling south with 25 N of force. What is the net force?

55 N south

Suppose a 60.0-kg gymnast climbs a rope. What is the tension in the rope if he climbs at a constant speed?

588 N

A light inextensible rope is used to pull a particle of mass 2.5 kg along a rough horizontal plane. If the tension in the rope ( applied force) is 25 N and acts at an angle of 25◦ above the horizontal and the coefficient of kinetic friction between the particle and the surface is 0.55, what is the acceleration of the particle?

6.0 m/s^2

Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is

60 km/h.

A stonecutter's chisel has an edge area of 0.7 cm ^2. If the chisel is struck with a force of 42 N, what is the pressure exerted on the stone?

600 000 N/m^2

How much work does a supermarket checkout attendant do on a can of soup he pushes 50 cm horizontally with a force of 15.00 N? Express your answer in joules .

7.5 J

Gravitational Acceleration "g" on the Earth has the magnitude of

9.8 m/s^2

Referring to the following figure, the correct relation is:

A +B = C

Which one of the following is NOT consistent with a car which is accelerating?

A car is moving with a high speed in straight line

What force makes you feel lighter in the water?

Buoyant force

Which of the following is not an example of a fluid?

Clay

Which of the following is not an example of a hydraulic system?

Computer

The law of ______________ of energy states that energy cannot be created or destroyed.

Conservation

As you climb higher up a mountain, air pressure would:

Decrease

An increase in the depth of water creates what kind of change in water pressure?

Increase

Question 15 At what point in its path is the horizontal component of the velocity (Vx) of a projectile the smallest?

It is the same throughout the path.

lf an object has a density of 14g/cm^3 and it is put in a container of water, what would happen to it?

It would sink

Which of the following is not a unit for power?

Joule

In order for an object to float in a container of water its density must be:

Less than 1 gram per cubic centimeter Equal to I gram per cubic centimeter

A ball is projected into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is ______________.

Less than 100 J. or 100 J.

Which law states the need to wear seatbelts?

Newton's First Law

Which of Newton's Three Laws does the following statement satisfy? An object at rest tends to stay at rest and an object in motion tends to stay in motion in a straight line at a steady speed until an unbalanced force acts upon it.

Newton's First Law

Which of Newton's Three Laws does the following statement satisfy? The relationship between an object's mass (m), its acceleration (a), and the applied force F is F=ma. Acceleration and force are vectors. This law requires that the direction of the acceleration vector is in the same direction as the net force vector.

Newton's Second Law

Which of Newton's three laws does the following example illustrate? If you have a hockey puck sliding along a table, it will eventually come to a stop.

Newton's Second Law

: When a crown of mass 14.7 kg is submerged in water, a scale reads only 13.4 kg. Is the crown made of gold? density of the water = 1000 kg/ m^3 or 1g /cm^ 3

No , because density of that crown is 11. 3 g/cm^3

A hydraulic press allow large masses to be lifted with small forces as a result of which principle?

Pascal's

Which of the following is Archimedes' principle?

The buoyant force of an object is equal to the weight of the fluid displaced by an object.

An object's inertia depends on its mass.

True

An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high it gains ______________.

Twice as much potential energy.

Car A has a mass of 1000 kg and a speed of 60 km/h, and car B has a mass of 2000 kg and a speed of 30 km/h. The kinetic energy of car A is ______________.

Twice that of car B

What is the path of a projectile (in the absence of friction)?

a parabola

Bronco is a skydiver. His mass is 100 kg. What is his weight in Newtons?

around 1000 N

Which requires more work: lifting a 50.0 kg crate a vertical distance of 2.0 meters or lifting a 25.0 kg crate a vertical distance of 4.0 meters?

both require the same amount of work

If an object has an acceleration of 0 m/s^2 , then one can be sure that the object is not ______________.

changing velocity

A truck driving along a highway road has a large quantity of momentum. If it moves at the same speed but has twice as much mass, its momentum is ______________.

doubled

If an object is moving eastward and slowing down, then the direction of its velocity vector is ______________.

eastward

A football is kicked into the air at an angle of 45 degrees with the horizontal. At the very top of the ball's path, its velocity is?

entirely horizontal

A football is kicked into the air at an angle of 45 degrees with the horizontal. At the very top of the ball's path, its acceleration is? (ignore air resistance)

entirely vertical

According to Newton's Third Law, action and reaction are

equal and in opposite directions

Which of the following is defined as a push or a pull?

force

A fullback is running down the football field in a straight line. He starts at the 0-yard line at 0 seconds. At 1 second, he is on the 10-yard line; at 2 seconds, he is on the 20-yard line; at 3 seconds, he is on the 30-yard line; and at 4 seconds, he is on the 40-yard line. This is evidence that

he is moving with a constant speed (on average).

Renatta Oyle is again found driving her '86 Yugo down Lake Avenue, leaving the following trail of oil drops on the pavement. If her car is moving from right to left, then ...

her velocity has a leftward direction and her acceleration has a leftward direction.

The tendency of matter to remain in constant motion unless acted on by an outside, unbalanced force is called

inertia

Salt water is more dense than fresh water. A ship floats in both fresh water and salt water. Compared to the fresh water, the amount of water displaced in the salt water is ______________

less

If car A passes car B, then car A must be ______________.

moving faster than car B, but not necessarily accelerating.

The speed-time graph for a particle moving at constant speed is a straight-line ______________ to the time axis.

parallel

As an object speeds up uniformly , its ______________.

speed increases

Weight is best described as

the downward force exerted on an object due to gravity

As in the video "A bullet shoot vs bullet drop", the measurable times were

the same

A boat moves through the water in a river at a speed of 8 m/s relative to the water. The boat makes a trip downstream and then makes a return trip upstream to the original starting place. Which trip takes longer?

the upstream trip

A 1200 kg car and a 2400 kg car are lifted to the same height at a constant speed in a auto service station. Lifting the more massive car requires ______________ work.

twice as much

Which type of quantity is characterized by both magnitude and direction?

vector

If an object is moving eastward and slowing down, then the direction of its acceleration vector is ______________.

westward